I have two Schedule C Car & Truck expense worksheets. Part I Line 8 on one of them calculates right, the other is calculating wrong. How do I fix it?

Having problems with the Schedule C - Car & Truck Expense Worksheet.  The same worksheet for the same vehicle calculated right last year, but this year it won't work.  I have a vehicle that was reported for the past few years and disposed of it this year.  Part I Line 8 is dividing the miles incorrectly.  Is there a way to fix it?  Do I have to delete the form and hope it'll allow me to re-enter an existing vehicle?