Please read the following directly copied from a Chase letter that came with a refund check (from normal refund that had sit in account for 3 months with no activity so a check was auto-sent.)
Enclosed please find a credit balance refund check to reimburse you for the current credit balance on your account. Please understand that if the credit balance was due to an overpayment made for your full account balance and the refund was requested in the middle of your billing cycle, you may receive a statement for subsequent interest charges assessed from the date of your previous statement until the date your full payment was received.
I have no inclination to find out exactly what the above wording may mean and how it would affect you if you intentionally overpay your Chase CC, then request the overpayment the following month mid cycle. Those who still want to try can report back the actual outcome for the benefit of the community.
