Yeah, the Asset Entry Worksheet is not set up for variable-business percentage.  For the Basis, it uses the current year business percentage, rather than the average percentage (see option #2).

Option #1:  Only enter the disposition date and leave the sales price BLANK on the vehicle sheet.  Then use the "Enterable 4797" to manually enter the information for the gain.

Option #2:  (a) Take the AVERAGE percentage and DIVIDE it by the CURRENT year percentage.  (b) Multiply that by the purchase price/Basis.   (c) Enter that result on Lines 54 and 55 of the vehicle worksheet.   It looks funky on the worksheet, but the proper numbers should flow to the 4797.