That is a silly frustration. There is no penalty for early payment of the loan so take the deal, pay it off it really bothers you.
~30k should have literally zero impact on your credit score even if you keep the free money and just pay off the loan. Unless I guess that your income to LTV is...
Denver Colorado here. Tynans nissan purchase.
10/7/2016 purchase of a 2016 Pearl White SV + floor and cargo mat & splash guards
32314.54 + 549 dealer fee so
32863.54 sale price
- 6,000 dealer and NMAC 0%
$26,863
- 7500 federal
- 6000 colorado
= $13,363.54
Use my numbers and do better...