I wonder if that's why they bumped up my credit limit?

I do this:

'...make two payments each month -- one just before the account's statement closing date and another just before the due date.

The first payment will reduce the balance that is reported to the credit bureaus and is used to calculate your credit scores.

The second payment ensures your account won't be marked late, since many issuers require some kind of payment between the statement closing date and the due date, even if a payment was made earlier in the billing cycle.'

9 big credit card myths