Is the only revolving line you have the AU account? If so, that could be your ding right there. Your only revolving account is paid to zero. Also, some versions of FICO doesn't factor in AU accounts. FICO likes to see responsible use of credit. A zero balance, while everyone knows that's best logically, doens't show use. A small balance is better than a zero balance in terms of FICO. It's recommended to have all credit cards but one report zero balances. Then the one that reports should be between 1-9% UTIL for optimal scoring. You can use the card(s) as much as you want througout the month but before the statement cuts pay off and down accodingly to get the one card to report that small balance. If you're not actively seeking credit, the UTIL isn't as big of a deal but you should always try and stay under 30%.
It would not be a bad idea to get a credit card of your own. With a thin file anytime you open up a new account your AAoA will take a small hit. Try the Cap 1 prequalify website to see if you can get approved for one of their cards. Before you app, do the prequalify and post the results in the credit cards forum. So much Cap 1 knowledge there. You'll probably hear to app for one card and if approved, immediately app for a second card.
