or maybe like foxtrick handels it in HT, that you cann't raise with factor 10 ... So if you want bid 100.000$ on a player who stands at 1$ you ahd to first raise to 10.000$ and the bid 100.000$.
The bad think of withdrawal bids, is that they effekt other bids, and in most case works pretty bad in the last minutes of the auction(so it is forbidden in the must propose their when the proctetion is needed must because the most bids come)