Hello madsmad,
That is unusual as increments in USD should be $5.00 for items between $250.00 and $499.00, you can see the list here http://www.auctionsniper.com/faqebay.aspx#ebay5.
I would suggest entering the maximum amount you're willing to pay, every time you add a snipe, to maximize your chances of winning.
Will you provide the item number of the item you're bidding on please?
Thanks,
Steve
Auction Sniper Product Manager