I'm going to Vegas in a couple weeks and booked and paid for my flight and my hotel on my CC. My USAA credit card has a 25 day grace period with 0% interest so I paid the amounts online before I even got the bill to avoid paying interest (about 9% APR). Was that a foolish thing to do in regards to showing payments and raising my credit score?
FICO can only score what is visible to it in your credit reports. It doesn't even have your monthly income to work with, so it can't even estimate your cash flow. If your reports show a long history with a number of tradelines, all "paid as agreed", high credit limits with low balances, no lates, and no collection accounts, what else is there? The only ambiguous issue is for accounts that don't show a maximum credit limit, but only a high balance, but if you have several other accounts that show full information, and overall low net balance to credit limit, this shouldn't matter much. If you pay ahead, it will just limit the blip in your debt to limit ratio, but unless this will somehow critically affect some pending loan, I doubt that most of your creditors will even notice it.
