We recommend that after every 3 rounds you update the POR this way there is always recent document on file. Just be sure that when you upload a new one that the previous POR is removed from the type of Proof of address and placed in as supporting doc. This way we only mail out the new one.  This following video will may also help you: https://scoreinc1.wistia.com/medias/n9jbwpp3q7