I am sure there are numbers in "Mr. Boeings" draw but not accessable to us.
Our Company uses the conservative method as well: RTO = Thrust Lever close, A/T disconnect, monitor AB, Speed brake Lever manualy deploy, then use Reverse and stop the Airplane on the paved surface. The F/O notifies the Tower and then we evaluate the situation what further action is needed.
I hope that helps. Hopefully eager Chief Pilots are clever enough to reinforce to follow Boeings proceedures closely. In case one of his troopers rests the Airplane after an RTO in the mud the BIG question will be: Who´s fault is it? and if there is a deviation from recommended proceedures then the Insurance Company is asking uncomfortable questions and the head of accounting starts to sweat....
Fly safe and land happy
NG