Hi Marniem,
I'm not sure if anyone else is here right now, but I'll do my best.
(and I'm a bit new, myself)
Auction Sniper only enters your bid at the time you specify. A snipe, loosely defined, is a last moment bid.
However, if the maximum bid you have specified in your snipe is topped by another bidder earlier in the bidding, then Auction Sniper will notify you immediately that you may wish to reconsider increasing your maximum (because at that point, obviously, your maximum is not enough to win).
Does that make sense so far?
Neva