We were quote the same when we had Cummins (Coach-Care in Avondale, AZ) do the replacement for us. the reason for the high quote was that it often takes just one whole day to get the bolts off as they usually break and have to be drilled out. We were lucky, only one bolt broke and it was half-way out and they were able to get it out so the whole thing was done in less than a day. At the time we were one of 5 coaches in there to have the same thing done - we were lucky, most were having to wait 2 days for their repair to be completed.
Barb