The only thing 50 AMP does (vs 30 amp) is let you run BOTH a/c units at the same time. Those that say they run 2 units on 30 amps at the same time, are taking a chance with electrical overload and that can equal a fire. Run both on 20AMP? Hope a fire extinguisher is nearby. IMO a definite recipe for disaster. Again...my opinion.
I have no idea why any coach company would market a unit with 2 a/c units and give 30 amps. IMO (again) that is not only dangerous but stupid. But then, I've seen new units at RV shows with no electrical outlets in the kitchen! How dumb is that?