It may be standard, but it isn't proper to say 'high bid' when it isn't the high bid.

http://en.wikipedia.org/wiki/Proxy_bid

In a normal situation that would not matter because you would hold on to your money. In a pre-pay system this is total nonsense because you are paying first to pre-pay for your account (on the one item that you may be interested in) and afterwards you bid using your credits. Because of the two stage nature of the process there is now a ratchet, you've already paid your money, now you find that it was useless.

Major design flaw.

The bidding is normally decoupled from the actual payment, by moving the payment up-front the whole thing breaks.