There are other things to cloud the picture.Finance charges,lower sale price with higher loan % rate.Cash is king,after you make the deal.
You may get the dealer to include a fifth wheel hitch or other extras.
Be leary of extended warranty deals,a lot of items are covered by mfg warranty.
The dealer has to make a buck,or go out of business,there is always the chance that you could get a few more $$ off,but if you walk away feeling fine about the whole deal,then don't try to second guess yourself.Coulda,woulda,shoulda thinking is a waste of time.