Welcome to Flyertalk. There are two features that might be confused.

Some US Airways cards offered a 10,000 miles/year bonus based on spending. If your card had that feature it could have carried over when converted to AAdvantage, but if it did not have it when it was a US Airways card, it doesn't apply.

Separately, cardholders receive a 10% refund of AAdvantage miles redeemed each year, up to a maximum of 10,000 miles.