RE:Hopefully
My reading of the FDA website suggests that pre-BTD is a process where you run your application by a designated reviewer who tells you whether likely to fly or not. So not a complex thing but rather a short way of the FDA saving yours and their time by telling you to proceed with BTD or not. TLT has always called this pre-BTD and no one else does that I can tell. I assume that there is enough communcation within FDA that that pre-BTD and BTD reviewers are aware of what each other are doing and if the the pre-BTD person comes back with comments such as (example only) "strong application but would benefit from central lab and post 450 day data" then you have to take the hint that they are saying that you may get BTD but it is more likely if you come back with these things.
So my guess is that pre-BTD would be quick if they did it last year already and are just circling back with, "yes the central lab data confirms things" and "post 450 data looks good", what do you think about BTD now. The pre-BTD reviewer would then direct them on readiness for the formal BTD application which has a max 60 day turnaround.