Im not 100% Sure, you'd need to wait for some a little more clued up than i am on this, im a 'Heavy' engineer, if it involves avionics or working these things out, count me out aha.
But racking my brains, not 100% if this is entirely correct, but your V speeds, even though shown on your IAS speed tape, theyre still calculated with; weights, temperature and flap settings.