About 3-4 days before statement end period for me...
I usually schedule payments on the due date using the AMEX website (I do that when I get the statement - again with payment on the due date) however in the past I forgot a couple of times and did that late (after the due date but never before the new statement was issued) over the phone and was never charged a penalty... so I guess it's OK to pay a little late provided you don't abuse it ?!
Agree! I like my cash flow.We just pay before the end of the month, despite the 14th pay due date.
IME, paying before the next statement date seems to cause no issue.
If the balance is high, they may contact you - if so, just explain when you will pay and that should be sufficient. (They may ask you not to employ use card in the meantime.)
If no contact, then just pay as you are going to do.