Monoploe,
V2 for a lower weight on the same runway is often higher
The FMC generally calculates the V speeds.
In any case as the weight reduces the aircraft does accelerate faster, and less brake energy to slow down again. Keeping that in mind the aircraft even at the same flap setting can accelerate to a higher V1 and stop in the same distance as a heavier aircraft, thats the speed the FMC produces.
At lower weights, generally you would use a lower flap setting, of which the options are unlimited, i.e. 5.6 degrees 5.7 degrees and so on. lower flap settings = higher V2
I agree that people shouldn't beleive
anything they read on here without supporting evidence. We all make mistakes and
we don't know what we don't know.