Personally with 800 left on Auto Loan most likely you have less then 10 months to pay. So that loan will not impact your DTI.

If you have credit card debt, that is where I would apply the extra payments to for a score boost. If you have no credit card debt, then you need to figure out what negative accounts you have and see what you can do to improve them.

Paying off a 800 installment loan will have very little impact if any impact at all in your scores.