The South Carolina Workers’ Compensation Commission (Commission) determined that Allie James (James) was totally and permanently disabled from a work accident. The circuit court affirmed the Commission’s denial of James’ request to put proration language in the order over the objection of Anne’s, Inc. and Villanova Insurance Co. (Respondents). We affirm.
FACTUAL/PROCEDURAL BACKGROUND
James was injured when she fell down steps while working at Anne’s Dress Shop. When she sought worker’s compensation benefits, the Commission found she was totally and permanently disabled and entitled to 500 weeks of compensation, with a credit for the weeks of compensation already paid. The Commission also found a lump sum payment was in James’ best interests.
James requested the Commission include in the order language prorating the award over her life expectancy, calculated using the table found in S.C.Code Ann. § 19-1-150 (1985 & Supp.2008). Respondents objected to the inclusion of this language, and the Commission found it lacked authority to include the language over Respondents’ objection. The circuit court affirmed. James appeals, arguing the Commission has the authority to include proration language in a lump sum award without consent of Respondents and that it was error not to do so in this case.
STANDARD OF REVIEW
An appellate court may reverse a Commission decision when that decision is affected by an error of law. Grant v. Grant Textiles, 372 S.C. 196, 200, 641 S.E.2d 869, 871 (2007). “Review is limited to deciding whether the commission’s decision is unsupported by substantial evidence or is controlled by some error of law.” Id. at 201, 641 S.E.2d at 871.
LAW/ANALYSIS
James argues the Commission has the authority to order life expectancy proration language over the objection of the Respondents. We disagree.
*329The question before us is whether the workers’ compensation statute allows the Commission to implement a specific procedural mechanism for releasing James’s funds. We agree with the circuit court that on such procedural questions, courts must strictly construe the statute and leave the definition of any ambiguous terms to the legislature. Callahan v. Beaufort County Sch. Dist., 375 S.C. 92, 96, 651 S.E.2d 311, 313 (2007).
James claims S.C.Code Ann. § 42-3-180 clearly gives the Commission the ability to enter proration language without consent of both parties. Section 42-3-180 states that “[a]ll questions arising under this Title, if not settled by agreement of the parties interested therein with the approval of the Commission, shall be determined by the Commission, except as otherwise provided in this Title.” Contrary to James’ position, this statute does not address the Commission’s authority to place proration language in an order. While it commands the Commission to answer questions arising under the statute, it does not allow the Commission to extend its powers beyond the scope of expressly authorized actions. Nothing in the statute authorizes the Commission to use life expectancy proration language without consent of both parties. Without an express grant from the legislature, the Commission is without that power.
James contends that the proration language is necessary to maximize both her workers’ compensation and Social Security benefits. Federal law requires a reduction in Social Security payments when the combination of monthly Social Security payments and monthly workers’ compensation benefits exceeds eighty percent (80%) of the claimant’s pre-disability income. 42 U.S.C.A. § 424a (2003). However, the Social Security offset provision does not apply if a state enacted its own “reverse offset” provision limiting workers compensation benefits prior to February 18, 1981. South Carolina did not legislatively adopt a reverse offset provision in that time.
As James concedes, the proration of this lump sum award is intended to have the same effect as a reverse offset provision — to maximize her award. Although we recognize that the Social Security Administration modifies its payments to account for lump sum awards that are prorated over a *330claimant’s life expectancy, we remain convinced that the Commission must derive its authority to do so from the legislature.
CONCLUSION
We hold that the circuit court and the Commission were correct in concluding that the Commission did not have the authority to prorate James’s lump sum award over her life expectancy without the consent of both parties. The authority of the Commission is statutorily derived, therefore, the Commission cannot exceed the scope of the legislature’s grant of authority. There is no specific grant of authority to the Commission to order life expectancy proration language absent consent of both parties. We affirm the circuit court’s ruling.
KITTREDGE, J., and Acting Justice JAMES E. MOORE, concur. BEATTY, J., dissenting in a separate opinion in which WALLER, J., concurs.