"Jennifer claimed permanent partial disability under SDCL 62-4-6(24) which allows compensation for permanent partial disability. In order to compute the statutory compensation allowed, a claimant must be evaluated and given an impairment rating.... Here, the physician used the Guides, Jennifer's medical history, and his professional experience to determine Jennifer had a 10-15% impairment rating. And while the Guides do not contain ratings on Jennifer's specific injury, they do contain methods for evaluating respiratory injuries. The physician further explained that while under one of the Guides rating tests Jennifer would show no impairment, she nevertheless has a permanent injury to her lung, greatly increasing her risk to redevelop the condition and increasing her susceptibility to pneumomediastinum or pneumothorax. Consequently, at trial, the physician testified that Jennifer had a 10 to 15 percent whole person impairment under that portion of the Guides that allow independent physician assessment when the specific injury is not covered. Although we acknowledge that the physicians methodology was subjected to substantial critical review in his deposition, that deposition was incorporated into the trial record, and the trial court ultimately found that a 10 to 15 percent impairment did exist. Whether and to what extent an alternative method is proper, credible, or permissible under the AMA Guides are questions of fact to be decided by the board. Rainville, 732 A.2d at 413, 143 N.H. at 632 (citing City of Aurora v. Vaughn, 824 P.2d 825, 827 (Colo.Ct.App. 1991) (as trier of fact, agency entitled to rely on expert testimony supporting deviation from AMA Guides)). Here, this matter was tried before the circuit court, and that trier of fact found the physicians alternative methodology credible. Considering the totality of the evidence, we do not conclude that the trial courts finding was clearly erroneous."