It's true that you won't ever pay more than your maximum, but it could mean you would pay much nearer to it. If I were being mean spirited, I could see your 5 bids and bid the current highest bid plus the current bid increment minus one penny and continue to do so until I've outbid your second highest bid. Granted this wouldn't be painful in the 15, 16, 17, 100 case but does anybody actually bid like that? But if it were 15, 25, 35, 45 then it becomes more costly.
One early low bid followed by a last minute snipe is the safest option, as long as you have a reliable reminder mechanism.