Are you sure you're not playing me. You just financed the car and you.re already under book value without paying extra towards the principal... u must have gotten a good deal.
Otherwise...
You could be right CU would have been my first option but if they only going solely off the scores ... you only bank with one of them right??
I'm not 100% certain but i think car book values drop every calender year ... I would hope someone corrects me if i'm wrong. This would give you some time to clean up as much as you can before years end. So for instance the 12 month plan would put you in a point were you made payments dropping what you owe but also the car will depreciate by a given amount can't say how much but could be a few grand depending on how old the car is/make/model that good stuff. Just to give you reference. I'm definately not gonna predict amounts just wanna give you insight as to what may be going on here.
Unfortunately i don't know a particular bank I normally go thru my cu as well they never offer me something in the range of 17 well 13 with similair scores. However someone else out there could give you the name of a bank that can give you a competitive rate that would be worth the refi.
