The POS criteria are related to the requester and not an attribute of the ticket. So different agents, web sites, companies, etc. will see potentially different availability for the same ticket (re-issue has nothing to do with it, or so I have been told). In theory every single availability request can be filtered with different rules, but in practice I think airlines do very little of that, and primarily use it to limit availability for some "deep discount" distribution channels prior to the original ticket issue (and rely on the fare rules to limit availability after issue). Again I have no inside knowledge of airline policy, this is just based on my own observations and reverse engineering of what various airlines appear to be doing.

Your question was answered over 2 years ago on FT, in Nov 2004 in this thread: http://www.flyertalk.com/forum/showt...40#post3380501