Considering the FAST is shot from full concealment, there is more to it than just pure shooting skill.
There are a lot of high level shooters who never draw from concealment.
Heck I know a lot of high level shooters who don't even own a gun that they could conceal, much less a holster and are well practiced in clearing cover.
Another thing I've noticed is many of the top shooters aren't any faster or more accurate on the trigger than a good B shooter. Shaving .05 off of your splits and .15 off your draw doesn't add up to enough time over a stage to separate a B from a GM. Where the A's and GM's are smokin fast is how they move through a stage and engage targets.
The FAST is a stand and deliver test from concealment and I can totally see how someone who primarily shoots IPSC competition could flub it.