Question: Cythera uses Perform Dance (+12) in place of her Acrobatics Skill (Class feature for Dancing Dervish). If she has Boots of Elven Kind (+5 to Acrobatics) would that effectively give her +5 on top of Perform Dance, or does it add to her true Acrobatics Skill (+2 for Dexterity alone).
What about Masterwork Slippers (50gp), +2 on Perform Dance? Same idea?
I've always read Versatile Dance (and Versatile Performance, which it replaces) as meaning you're really making a Perform check instead of the requisite skill. So bonuses to Acrobatics checks wouldn't effect it; bonuses to Perform would.
If nothing else, I think it should definitely be one or the other; otherwise versatile gets a whole lot more easy to break by double-stacking bonuses.