it was a serious response...i didn't know you used store credit....had you used a full cash payment months early, you would not have anything except for a receipt and they would have your money to do with it as they pleased....so, say they put your $50 in the bank or invested it or some such thing instead of spending your money....and say for every $50 they do that with they make $0.001....well, after a while, if they have a lot of $50 deposits doing the same thing month after month, they will be making a lot of extra money that they wouldn't have been making, had you just given them the $5 that they usually require....plus, say in your situation they say that you didn't preorder it, without a receipt, you are out $50....had you only put $5 credit on it, you would still have the $45 other credit and you would have only been out $5 due to their error, not $50
so, the wise thing to do in a preordering situation is to only put down the bear minimum amount, unless their is some great incentive that you would get for paying it off, such as maybe 10% off total if paid off early, or someting to that effect....