Gaines v. Sun Refinery and Marketing, 790 P.2d 1073, 1076-1077 (Okla. 1990). Language to the contrary in Case v. Mack Trucks, 773 P.2d 765, 766 (Okla. App. 1989) is hereby disapproved. This has not always been true. 85 O.S.Supp. 1978 ยง 3[ 85-3](11) allowed for assessments deviating from the Guides when the deviation was explained by the examining physician.