Our revision department cannot provide an estimate on interior edits until they see the edit sheet. Even then it is very difficult to give an estimate before actually implementing the edits. You can obtain a rough estimate from the revision department by sending them (firstname.lastname@example.org) the required edit sheet once you have paid the Post-Publication Revision set-up fee.
You can start the revision process by logging into your author center and going to the Publications Revisions tab. http://www.outskirtspress.com/authorcenter20.php