In Alhjouj v. Special Indem. Fund, 1997 OK CIV APP 68, 947 P.2d 1117, claimant suffered from pre-existing twenty-eight and one-quarter percent (28.25%) PPD, twelve and one-half percent (12.5%) PPD from her latest injury, and a material increase of five percent (5%) PPD as a result of the combination of disabilities, for which the Workers' Compensation Court awarded her an additional 20 weeks of compensation from Fund. On claimant's appeal, the Court of Civil Appeals sustained the order of the Workers' Compensation Court, holding: . . . Fund's liability is purely derivative from the previously adjudicated obligation of the employer and Fund is responsible only for the amount of material difference in disability due to the combination of disabilities. . . . . . . Claimant suffered a previous disability, and was compensated for her latest disability by her employer. The previous and latest disabilities are components of the combined disability which determines if Fund is liable, but both are wholly separate obligations. Fund's compensation supplements the others to ensure Claimant is fully compensated, but Fund is not liable for the entire combined disability, only the material increase. Accordingly, we hold that the 5% material increase comes within the first 9% of disability for which Fund is liable under 22(3)(b)(1). . . . The 5% material increase would have entitled Claimant to 25 weeks of compensation. In accordance with 22(3)(b)(1), Claimant is to receive compensation for 80% of the number of weeks provided by law . . . . Eighty percent of 25 weeks is 20 weeks, the number of weeks ordered by the Workers' Compensation Court. The Workers' Compensation Court ordered the correct number of weeks.