The government appeals the judgment of the Court of International Trade, 770 F.Supp. 641 (1991), that certain motor vehicle components are eligible for the trade allowance provided in item 807.00, Tariff Schedules of the United States (TSUS), despite a contrary determination by the United States Customs Service. We reverse.
Background
During 1986 and 1987, General Motors Corporation (GM) manufactured in the United States various sheet metal components for use in the production of motor vehicles. These components were shipped to Mexico and assembled, along with other components, into finished vehicles in GM’s Ramos Arizpe assembly plant.
The Ramos Arizpe assembly process is described as consisting of five operation groups: body shop, paint shop, chassis line, trim shop, and final process. In the first group, body shop, major component subas-*718semblies are fitted together and spot welded to create the body of the automobile. In the second group, paint shop, the body is cleaned and sprayed with a protective zinc phosphate compound, submerged in an electro deposition primer tank, baked, sanded, treated with a sealant, and then baked again. This is followed by an application of surface primer. At this point, topcoat (finish) paint is applied and the body is oven cured. Finally the body is waxed and sent along to the trim shop.
In the trim shop, certain internal components are installed and water testing is performed. Next, in chassis, while the radiator, grille, and gas tank are attached to the body, the engine, transmission, and frame are independently subassembled on a separate conveyor. The body and frame are then joined, and the bumpers, radiator, and tires are installed. The last operation is final process wherein manual detail work, sundry inspections, wheel alignment, and final drive tests are performed. The finished vehicle is then reshipped to the United States for sale.
Upon the re-entry of the vehicles at issue here into the United States, GM sought a tariff allowance for the value of the sheet metal components manufactured in the United States, in accordance with item 807.-00, TSUS. Customs granted allowances on some of the components, but, in accordance with its regulation,* denied the allowance to components that had undergone topcoat (finish) painting, because:
Finish painting vehicle parts is not of such a minor nature as to be considered incidental to the main assembly process .... [FJinish painting amounts to a fabrication that advances the vehicles in value and condition, beyond the meaning of [item 807.00].
After denial of its administrative protest, see 19 U.S.C. § 1514 (1988), GM filed suit in the Court of International Trade challenging Customs’ denial of the trade allowance on the disputed components. See 28 U.S.C. § 1581(a) (1988).
On July 23, 1991, the court entered judgment in favor of GM, holding that the topcoat painting operations were minor and clearly subordinate to the assembly process and, accordingly, were “incidental to assembly” as required for item 807.00 treatment. 770 F.Supp. at 648. The court ordered Customs to reliquidate the entries and refund excess duties paid, with interest, to GM. Id. at 642.
Discussion
Item 807.00, TSUS (1986), provides that:
Articles assembled abroad in whole or in part of fabricated components, the product of the United States, which (a) were exported in condition ready for assembly without further fabrication, (b) have not lost their physical identity in such articles by change in form, shape, or otherwise, and (c) have not been advanced in value or improved in condition abroad except by being assembled and except by operations incidental to the assembly process such as cleaning, lubricating, and painting [are subject to] [a] duty upon the full value of the imported article, less the cost or value of such products of the United States....
Accordingly, domestic components exported for assembly and reshipped to the United States, which conform to the requirements of each subpart of item 807.00, are eligible for a trade allowance upon re-entry in an amount equal to their cost or value.
*719In this case, there is no question that the disputed sheet metal components were exported in condition ready for assembly without further fabrication (807.00(a)) and have not lost their physical identity in the finished motor vehicles (807.00(b)). Furthermore, the components have “been advanced in value or improved in condition abroad” by the painting operations performed in GM’s Ramos Arizpe assembly plant, as contemplated by 807.00(c). Therefore, in determining whether the components qualify for the item 807.00 trade allowance, the dispositive issue is whether the painting operations fall within the scope of “operations incidental to the assembly process such as cleaning, lubricating, and painting.”
GM suggests that this issue can be resolved solely by the plain language of the statute. It contends that item 807.00 “expressly enumerates painting as an acceptable operation incidental to assembly ... [and] explicitly cover[s] the operation at issue here.” We disagree. The statute’s reference to “painting” is simply an exemplar of an operation which is potentially “incidental to the assembly process,” not a definitive statement that all painting operations, no matter how extensive, are allowed under item 807.00(c). This interpretation is fully supported by the statute’s legislative history, as set out in United States v. Mast Indus., Inc., 668 F.2d 501, 505 (CCPA 1981)
The amended item 807.00 would specifically permit the U.S. component to be advanced or improved “by operations incidental to the assembly process such as cleaning, lubricating, and painting.” It is common practice in assembling mechanical components to perform certain incidental operations which cannot always be provided for in advance. For example, in fitting the parts of a machine together, it may be necessary ... to paint or apply other preservative coatings _ Such operations, if of a minor nature incidental to the assembly process, whether done before, during, or after assembly, would be permitted even though they result in an advance in value of the U.S. components in the article assembled abroad.
H.R.Rep. No. 342, 89th Cong., 1st Sess. 49 (1965) U.S.Code Cong. & Admin.News 1965, p. 3416 (emphasis added). Thus, contrary to • GM’s suggestion, the mere fact that the disputed operations involve painting does not resolve this appeal. Instead, we must focus on whether the operations are “incidental to the assembly process” within the meaning of item 807.00(c).
Whether particular operations are “incidental to the assembly process” has been at issue before. See, e.g., Mast, 668 F.2d 501; United States v. Oxford Indus., Inc., 668 F.2d 507 (CCPA 1981); Miles v. United States, 567 F.2d 979 (CCPA 1978). In Mast, the court had to determine whether buttonholing and pocket slitting operations performed upon fabric components were incidental to the assembly of women’s pants under item 807.00(c). After rejecting arguments that these operations were precluded merely because they provided “independent utility” or were not essential to the assembly process, the court concluded that “operations [such] as applying preservative coatings and testing and adjusting the components are incidental to the assembly process ‘if of a minor nature.’ ” 668 F.2d at 506 (emphasis added); see also Oxford, 668 F.2d at 510. As a means of ascertaining whether “an operation of a ‘minor nature’ is incidental to the assembly process,” the court set out the following factors:
(1) Whether [i] the cost of the operation relative to the cost of the affected components and [ii] the time required by the operation relative to the time required for assembly of the whole article were such that the operation may be considered “minor.” ...
(2) Whether the operations in question were necessary to the assembly process ....
(3) Whether the operations were so related to assembly that they were logically performed during assembly.
Mast, 668 F.2d at 506. But because it identified these as “[r]elevant factors in this case”’ id., we do not read Mast as announcing factors that must invariably be used to the exclusion of all others, or that *720all such factors are pertinent in every case involving item 807.00. We believe “Congress intended a balancing of all relevant factors to ascertain whether an operation of a ‘minor nature’ is incidental to the assembly process.” Id. We see this balancing process as an objective way to decide if particular operations are minor and incidental to assembly.
In applying the first part of the first Mast factor, the trial court said,
The Mast court unambiguously stated that it compared the “cost of the [challenged] operation relative to the cost of the affected component and the time required by the operation relative to the time required for assembly of the whole article.” 69 CCPA at 54, 668 F.2d at 506.
With reference to what operations are “challenged”, there is no doubt that all of the operations performed in the paint shop are not at issue herein. Customs itself noted in its rulings that the preservative coating operations that make up the rest of the paint shop operations were in conformity with the spirit of item 807.00. Therefore, for defendant to now demand the use of cost and time figures of all paint shop operations when performing Mast comparisons is irrational. Only the figures directly attributed to the challenged finish painting operations will render a truthful computation of whether the operation is indeed of a minor nature.
770 F.Supp. at 645. The court was correct that Customs allowed GM a trade allowance on components that underwent preservative coating operations, but this appeal involves different components, those which were also subjected to topcoat painting, on which a trade allowance was denied. Accordingly, we believe that all coating operations performed upon the disputed components, including zinc phosphate, electro deposition primer, sealant, surface primer, sanding, baking, and waxing operations, are relevant and must be considered in conjunction with topcoat painting operations to determine if coating operations, collectively, are minor incidents to assembly. The piecemeal analysis adopted by the trial court undermines item 807.00 by allowing major and significant operations to be broken down to a point where each step could be called minor. The court focused on its finding that “the cost of topcoating is but a fraction, i.e. 14%, of the cost of the affected components.” Id. at 646. But the appropriate cost comparison, encompassing all paint shop operations and using GM’s own cost data, reveals that coating operations are nothing if not major.
In applying the second part of the first Mast factor, the trial court observed that “the time expended in the topcoating operations accounts for less than four [standard labor hours] out of a total assembly time of over thirty-nine [standard labor hours].” Id. This time comparison, like the cost comparison, improperly excludes relevant coating operations. Nevertheless, while the comparison of labor hours, or total time of the operation, undoubtedly is relevant in some cases, where the operations are complex and involve significantly automated or non-labor processes (such as baking), this factor provides little guidance on whether operations are of a “minor nature.” It is entitled to little weight in this case.
On the remaining Mast factors, the trial court held that “[GM] has painstakingly demonstrated that for reasons of economics as well as design, the topcoating operation is most logically performed during the assembly process.” Id. We see nothing wrong with this finding, but it does not save the case for GM.
The record demonstrates that GM’s cost data on coating operations is significantly understated because its accounting methods do not fairly allocate the cost of paint shop equipment to the cost of the paint shop operations. Under GM’s accounting methods, depreciation costs are allocated to each department on the basis of the standard labor hours expended in the department, not on the basis of the actual capital investment. Accordingly, this does not fairly, allocate the real costs of equipment, notwithstanding that “this method of reporting time and cost is a standardized method in cost accounting for assembly operations” and is “authorized by GAAP,” according to GM.
*721We therefore believe capital investment in paint shop operations, compared with investment in the assembly processes, is relevant in deciding whether- the operations at issue are of a minor nature. GM’s data shows that the capital investment in machinery and equipment in the paint shop is more than five times that in the body shop, where significant assembly operations are performed. In sum, proper application of the first Mast factor; and consideration of overlooked information, confirms that the paint shop operations are not within the scope of item 807.00(c).
Conclusion
Accordingly, the judgment of the Court of International Trade is reversed.
COSTS
General Motors Corporation shall bear the costs of this appeal.
REVERSED.
19 C.F.R. § 10.16 (1986), in relevant part, provides:
(c) Operations not incidental to the assembly process. Any significant process, operation, or treatment other than assembly whose primary purpose is the fabrication, completion, physical or chemical improvement of a component, or which is not related to the assembly process, whether or not it effects a substantial transformation of the article, shall not be regarded as incidental to the assembly and shall preclude the application of the exemption to such article. The following are examples of operations not considered incidental to the assembly as provided under item 807.00, Tariff Schedules of the United States (19 U.S.C. 1202):
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(3) Painting primarily intended to enhance the appearance of an article or to impart distinctive features or characteristics