Seriously this issue had haunted me as well. Our facility is heavily vested in blackmagic, and to be honest it is starting to be a huge regret. We probably have about 15 cards at the moment and not one of them can lay off frame accurate. I have tried the frame offset thing but it does not consistently work. This is especially annoying when you are working in 23.978 and you go to do a down convert. That frame-off issue becomes even more of a big deal taking stuff from 23.976 to 29.97.
Considering switching to Kona,
Jake