If you paid $1070 filing fee for your I-485 and filed your I-765 concurrently with your I-485, then you do not need to pay the filing fee to renew your EAD. You should file the I-765 between 120 and 90 days prior to the expiration of your current EAD.
This answer is of a general nature and should not be relied upon as final, nor is it intended as legal advice. Consult with a qualified attorney before making any legal decisions. Gen Kimura, (832) 247-6932.