I think its pretty much a moot point at this juncture....they applied to present, at least in part, because this is obviously a prestigious venue to release results imo.  What possible reason could they have to "NOT" want to present now?  

I think I get the gist of what you're saying....why not bow out of AHA and present the data sooner.  Personally I can't see that even being a consideration....from the science side of things I assume they want to provide the information to the right people, in this regard AHA strikes me as being as close to ideal as you can get.