I would bet that Bucars RV doesn't do the work themselves. Most likely they send them out to a hydraulic shop, and then add a hefty mark up.
I guess the advantage of taking the levelers off yourself and taking them to a repair shop is that the shop doesn't see your nice rig and assume you have "money to burn"
Are you sure that all the hydraulic legs need to be repaired? It would be unusual for them all to go bad at once, but not impossible.
I guess that before I spent any money I would want a reliable diagnostic evaluation of the entire system. It would be a shame to spend big bucks on rebuilding all four legs only to find out the pump seals were bad or some other related problem.
The beauty of a motorhome is that the tinkering never ends.