I've wasted my day, so you can too - How Oppo is your car?

Inspired by Davesaddiction, I decided to do a spreadsheet version with a version with inputs. Most of the stuff is the same, but I’ve changed a lot too. It’s probably rife with “error”. Error is quoted because the real question to ask is - is there a right answer?

Anyway, here is the link, hopefully, it works for you.

HA! Just kidding!  Its going to Davesaddiction to meld it with his work, it will be back.

Download the spreadsheet to play with it, you wont be able to make changes from the link