OK, I've been looking everywhere, but I can't seem to find an up to date source on the attack speeds post update 5.
DDOwiki says there's still an increase in attack speed on BAB 10,15 and 20, but I think this might be old information (I believe they changed it to that in update 2, but removed that when they altered two weapon fighting).
Beating the dummy with a BAB 9, 15 and 20 all seemed to result in 86.5 attacks per minute for me. (I used a single dagger without haste buffs, but I don't think style or weapon still matters, does it?)
Is there really a difference?