Are you referring to the -8 with regard to the "speed band" or do you think the -400 also thinks that far ahead?
That is an interesting observation you make and would explain why probably every time I have seen DRAG REQUIRED, I have been doing less than MMO/VMO - 16.
It sure would be nice to see something in writing on this, but I can't seem to find much. The FMC User's guide is no help here.