Thank you very much southsidesilver!
So, if I am not mistaken your point..........
I had total of $1000 in my card initially and paid $400 on 07/20. I can make another payment of $580 again after 07/27 and keep the $20 rolling till next month. Will this work?
Yep you can probably do the entire $600 after 7 days because you will be back to the $800 amount again.