Yes it is typical, you are lucky the non selling dealer even accepted your coach.
Reason for this is do to several factors.
First its very difficult to find RV technicians, so that resource is limited.
Warranty work is costly to the dealer, as manufacturers don't necessarily cover all costs, customer pay work does. Again, only so many service hours available.
A smart dealer expects to have units come back for warranty work so out of the profit he (hopefully) made from the sale of the coach, he sets some aside to cover future warranty costs. Since you bought elsewhere there is no profit to offset your warranty costs, so the dealer has little incentive to put your coach at the head of the line.