Hi Check Airman!
Correct me if I am wrong but the speeds calculated by a Boeing FMC are just weight/config dependant?
It will be rather difficult to implement this feature in an Airbus FMGS because the Vspeeds in a FBW Airbus are always optimized in order to achieve maximum flex (=assumed temp). In other words: Airbus Vspeeds are nearly always based on improved climb technique and among many factors are largely dependant on the runway.
The consequence is less transparency for the pilots: very low TOW can produce some very high Vspeeds and vice versa.
Hope this helps!
PS: gross error check is done by many operators by comparing ¨Green Dot¨ speed (=minimum clean speed) between the FMGS and the Performance program. This happens to be the only speed calculated by the program which is purely TOW dependant!