Willie Everlearn,
I suggest you check out FAA AC91-6B regarding contaminated runways using a 15ft screen height and reverser thrust.
Rainboe, the FAA certified the B747-400 using the constant velocity transition method for the accelerate stop. Basically, Vef is 1 second prior to V1, then they use the demonstrated brake, spoiler , reverse time FOLLOWED by 2 Seconds at a constant velocity before the aircraft is assumed to be decelerating.....
This method applied to the 737-300/400/500. B757-200, B767-200/300 and B747-400. The following are the various methods used by Boeing:
Willie Everlearn, you just explained how the B707,B727,B737-100/200, B747-100/200/300 were certified.
Mutt
Mutt