There's no weight transfer on a 5th wheel and I highly doubt any MFG figures weight transfer when designing a trailer.
Your 27.5BHS only weighs 7195lbs dry with a pin of 1340lbs. I highly doubt you'll load 2755lbs of stuff in it. Even if you load 2000lbs that puts you at 9195lbs and you should have a pin around 1800-2000lbs. Minus the 1800 from say 9200lbs and you only have 7400lbs on the axles. With 4400lb axles you are fine. You have a cushion of 700lbs per axle. Even D rated tires give you plenty of cushion. You won't get 5200lb axles until you get into more robust built 5th wheels.