The Stage Right release time is dependent on the fluid volume at the time of the shift, how quickly you move the lever and temperature of the fuid in the trans (the heat effects the tension of the shift valve springs).
With a BAT brake, the second point above is moot (assuming your transrake button is set up like a hair trigger). I would think that the first and third point will apply to any transbrake...yet they are pretty minimal and prolly hard to measure their effect(s).