It all depends what kind of auction we're 
thinking of.  Sure on ebay your max bid is not 
bid up to. But thats an ebay auction.  Think 
about how live auctions work.. like the art 
auctions at an anime convention.  You call out 
your current bid.. and that is what you pay if no 
one calls out something over you.  

Really silent auction is the same as making 
offers on a cel.  If someone says they're taking 
offers on a cel, what you offer is what you pay.  
Same concept. 

Not that there's anything wrong with not liking 
this method.  I personally always drive myself 
crazy when trying to make offers, second guessing 
myself and wondering if I paid too much.  But at 
the same time I have gotten some beautiful cels 
this way (like my Sara pan cel), and they were 
worth what I paid to me.  Congrats to the person 
above on that Arai-kun cel.  It leapt out at me 
as well when I saw it.  Sotsugyo M cels are SOOO 
hard to find!

Anyway back to my original point.. because this 
is the way the auction is being run, I assure you 
the person selling the cels is the one who gets 
whatever you offered, Celga doesn't keep any of 
it.