Employer seeks judicial review of a final order of the Department of Insurance and Finance (DIF) holding him liable for an additional premium for workers’ compensation insurance. We reverse.
Employer is a construction contractor specializing in the installation of roofing. SAIF is employer’s workers’ compensation insurance carrier. Beginning in 1981, SAIF approved employer’s use of three risk classifications for the work activities of his employees. That use continued through 1988. In 1989, SAIF audited employer’s 1988 payroll and charged him an additional premium of $5,887.05 for that year. Before the audit, the work activities of the employees affected by SAIF’s payroll change were grouped in risk classifications 5645 and 5551. After the audit, SAIF determined that their work activities should all be placed in classification 5551. Employer requested a hearing by DIF, at which he argued that SAIF was not entitled to make an additional assessment for 1988, unless it complied with the requirements of ORS 737.310(12). DIF ruled that SAIF’s actions did not fall within the purview of ORS 737.310(12). Employer seeks review of that ruling.
ORS 737.310(12) (since amended by Or Laws 1991, ch 768, § 1)1 provides:
“At the time a workers’ compensation guaranty contract is issued, the insurer shall give written notice to the insured of the rating classifications to which the insured’s employees are assigned and shall provide an adequate description of work activities in each classification. The insurer shall not bill an insured for reclassifying employees during the policy year unless:
“(a) The insured knew or should have known that the employees were misclassified;
*574‘ ‘ (b) The insured provided improper or inaccurate information concerning its operations; or
“(c) The insured’s operations changed after the date information on the employees is obtained from the insured.” (Emphasis supplied.)
In holding that ORS 737.310(12) is inapplicable, DIF said:
“Petitioner argues in its exceptions that the proposed order did not address [the] ORS 737.310(12) exception criteria. However, since SAIF did not base the premium increase which resulted from the premium audit on a reclassification of ‘employes’ there was no need to address the exceptions to the statute. Respondent SAIF adjusted Petitioner’s payroll reports to reflect higher payroll in Class 5551 and lower payroll in Class 5645. SAIF did not change the classification of Petitioner’s employes. Petitioner’s employes had both of these classifications prior to and throughout the premium year in question. * * * ORS 737.310(12) specifically addresses reclassification of employees. No where [sic] is it articulated that the statute extends to reclassification of payroll.”
An administrative agency is not at liberty to limit or restrict the terms of a statute. Cook v. Workers’ Compensation Department, 306 Or 134, 138, 758 P2d 854 (1988). Clear, unambiguous statutes are to be construed according to their plain meaning. ORS 174.010; Satterfield v. Satterfield, 292 Or 780, 782, 643 P2d 336 (1982). Under ORS 737.310(12), classifications for workers’ compensation insurance are based on “work activities.” “Reclassify” means “to group or segregate into classes again on a new basis” or ‘ ‘to move from one class, classification, or category to another.” Websters Third New International Dictionary 1896 (unabridged 1976). Thus, the plain meaning of the statute is that reclassification may occur by assigning the work activities to a new classification or by changing the classification from one class to another. “Reclassification” of payroll2 is simply the means by which the changes are accomplished.
*575 DIF’s ruling is merely an exercise in semantics. The effect of changing employer’s payroll from classification 5645 to 5551 is to change the classification of the work activities of employees on the basis of a different assessment of risk of injury. Under the plain meaning of ORS 737.310(12), that action constitutes a reclassification of the work activities of affected employees. Although employer had incorrectly allocated some of the work activities to classification 5645, ORS 737.310(12) requires SAIF to demonstrate that employer knew or should have known that the employees were misclassified or that the employer had provided inaccurate information or that work activities of the employees changed after 1981. In the absence of such proof, SAIF was not entitled to bill employer for an additional premium for 1988. DIF erred in holding to the contrary.3
Reversed.
ORS 737.310(12) now reads:
“At the time an insurer issues a workers’ compensation insurance policy to an insured for the first time, the insurer shall give written notice to the insured of the rating classifications to which the insured’s employees are to be assigned and shall provide an adequate description of work activities in each classification. In the event an insurer recommences coverage following its termination, the notice required under this subsection must be given only if the gap in coverage exceeds six months. The insurer shall bill an insured for reclassifying employees in accordance with rules adopted by the director.”
Although ORS 737.310(12) was not at issue in Mr. Lustre Car Care v. Nat’l Council on Comp. Ins., 99 Or App 654, 783 P2d 1032 (1989), we used the terms “reclassifying employees” and “reclassifying payroll” interchangeably. In that case, the petitioner sought review of an order that denied its “request for reclassification of a portion of its payroll for workers’ compensation insurance rating.” 99 Or App at 656. (Emphasis supplied.) In reciting the facts, we said:
*575“After that inspection, petitioner’s employes performing the clerical and cashiering duties described above were reclassified from Code 8810, covering clerical employes, to Code 8387, covering car wash employes. * * * In an inspection amendment, NCCI permitted a reclassification from Code 8387 to 8810 for clerical employes working only during hours when the car wash was not operating.” 99 Or App at 657. (Emphasis supplied.)
The dissent says that ORS 737.310(12) applies only to “reclassification” by assigning work activities to a new classification, as distinguished from assigning work activities from one existing classification to another. That interpretation is premised on the supposition that “[e]ach of these [ORS 737.310(12)(a), (b) and (c)] exceptions relates back to the date of the issuance of the policy.” 111 Or App at 576. Contrary to that premise, each of the exceptions relates to the policy year, not to the original issuance of the policy. ORS 737.310(12) refers to a reclassification “during the policy year,” which in this case was 1988. The issuance of the policy in 1981 is immaterial to SAIF’s attempt to charge additional premiums for 1988. Moreover, DIF cannot, by rule (OAR 836-42-060), as suggested by the dissent, limit the statutory requirement for the retroactive assessment of premiums. See Cook v. Workers’ Compensation Department, supra.