Sorry for the delay Ianian.

I have never checked to see which percentage of horses rise (or drop) in class.

As a stand alone statistic up or down in class (IMHO) doesn't have a great deal of merit. However as class is generally determined by allocated weight, (and using my own selection parameters) given the choice,I'd rather a back a horse going UP in WEIGHT off a last start win than a horse going DOWN in WEIGHT from a last start win.

Cheers

Privateer