This has changed:
a) all transactions go thru bank directly (no need to do manual transactions anymore)
b) bidders cannot bid more than they own in their bank account
c) The auction last 10 minutes + additional minutes if bidding continue. It stops after 60 seconds with no biddings
d) The slave gain 20% of the transaction, the seller 80%
e) The bank balance will be updated in your HUD, so you can quickly verify the bank transaction.