In the automotive world most mechanics can meet the flat rate times put out by their manufacturers. For tractors, there is not a prayer. Take the popular BX fender replacement that we did so many of two years ago... flat rate on that was probably around 1.25 hrs. Even someone who had done several of them took 3+ to get it done. So we eat the cost.
This sounds like a problem between manufacturer and dealership?
Does the manufacturer have individuals who can perform the change out in that time? Who determines the flat rate? Although not likely from what you said, what if you had a guy who could do the change out in less than that time ... you would make a profit then, right?
My point is that if manufacturer and dealer times agree, it would be profitable.
Cost of transportation can be passed on to the consumer, make that a clear stipulation ... thereby the consumer would take dealer location for warranty work into consideration because there's a cost involved to him.