It's likely that your bids were not received and processed by eBay in the order you expected. It's also possible/likely some of your bids were not recieved in time.
Lets suppose you enter the following bids.
9 seconds $20
8 seconds $21
7 seconds $22
3 seconds $23
2 seconds $24
Now suppose the 7 second bid of $22 wins and is the only bid to show up in the bid history. This is how that could happen.
If the $22 bid was sent early, the 9 and 8 second bids would be rejected by eBay as 'To Low' and would not show up. (you can't bid again unless your max is higher) The 2 and 3 second bids (because of heavy traffic) might have been 'Not in time'. Those other interested bidders, if they really tried to bid, got a 'To Low' or 'Not in Time'.
eBay does get slow durring high traffic times, but one person working by themselves is not going to cause it.
I've seen as many as 3 bids placed and recorded in the bid history with the exact same time. What's the max? I'm sure eBay will keep that secret to themselves.