Just as a point of reference, when I had our warranty work done in 2011, it was done by a non-Heartland dealer that was authorized for Heartland warranty work. It never took them more than a day or two to get authorizations from Heartland for any given work. It would have to be some extraordinary repair issue for it to take longer at the Heartland end. They also got quick authorizations from Dometic and Lippert. Dexter is also very responsive.
On the other hand, posts about dealers being slow to ask for authorization are as common as gravel at a KOA.