I've thought about that approach, just make a simple letter on why you are applying based on OP485A; less talk, less mistakes.
However, is it necessary to upload a copy of your recent OWP? If so, does it contain info as shown in the Issuance section:
http://www.cic.gc.ca/english/resources/manuals/bulletins/2013/ob485A.asp
Because this will tip-off the Officer that you were issued an OWP based on the PR Application (although it will be in the system anyway).
I think there's a really good chance since it's a new (and recent) AOR and not based on the old one.