You are clearly another victim of managements' "red-linning" tactics.
Your PM is incorrect, and if your PM gets thier info from the District, theay are also incorrect.
At this late date (If you haven't already submitted your dis-agreement forms to your PM), you do not have an option of having their decision changed.
There is a USPS memo sent to all district managers concerning the "red-linning" tactics, to try to suit the districts goals.
I can look it up for you if you require it for your greivience, if you are going that route.....
I have always found it helpful to be prepared to show District or your own PM..... THEIR own documents as proof of your dis-agreement.
Most managers will say "we do not allow documents that are provided by the union as proof".
(Example.... the NRLCA 2009 Mail Count Guide).
So, what I do is go to the USPS website, under Postal Bullitens, and do a search for the item in question.
Chances are you will find a revision to the PO-603 or some other document that IS THEIR material.
PRINTED by them, and meant to be read by all managers for policy updates.
The markups you have in question (If they are not contained in the PO-603 or MCGuide), can be found in this manner inside a postal bulletin. As well as a page from the DMM which lists ALL of the reasons for non-delivery accronyms.... UTF, NMR, ANK, etc....
The only other option you have if you are still being denied more than 7 mark ups, is to be sure you only process 7 marked upped pieces of mail THE REST OF THE YEAR. Let management do it or request to be paid for it on a 8127.