Let's the opening bid was 20,000.
Bidder 1 puts his max bid at 50,000
The auction only says the highest bid is 20,000, belonging to Bidder 1.(no-one has outbid him yet)
Bidder 2 comes along and see's 20,000 so he bids 25,000.
But bidder 1's max is higher, so that just bumps bidder 1's the...