On the one hand you're running v9 so the usual rule is "the greater of either warm bodies running interactive sessions or batch processes". From your description you would need to count the largest number of concurrent batch sessions. So you would need a 25 user license.
On the other hand if your batch processes are really a form of "connection pooling" (there are, for instance, several "webspeed alternatives" that fall into this category) then it gets more complicated. In that case you need to count the connections being pooled.
PSC sales weasels have been known to claim that if any data that ever resides in a Progress database is ever exposed by a web browser that you then need to license every possible internet user on the planet. (The weasel anti-defamation league is sure to sue me for that comment -- so please contribute to my legal defense fund...)
They are obviously insane when they make such claims -- the best defense is to laugh hysterically and offer to buy the next beer. Make it clear that you know that they were joking. Because if they smell even the slightest whiff of weakness they will put that "sale" on their forecast and then they will be painted into a corner that they cannot get out of. Ditto if they mention the words "platform change", "re-licensing" or "name change". These are code words for
really, really big unearned commission. It's a game of chicken and you will be road-kill if they have even the smallest inkling that they can get away with it. They will tell you with a straight face that there is nothing that can be done, that everyone is doing it and that those nasty evil people back at corporate are making them do it. Laugh again and buy them another beer. Remember that this is all about the commission. If you can redirect their attention to some actual money that you really will spend if they will simply come to their senses and stop fooling around before you have to regretfully inform your management that ... (I'll leave this as an exercise for the reader) A word or two about a bird in the hand vs. lots of birds in bushes might be constructive
OpenEdge 10 licensing cures the ills related to licensing every imaginable user on the internet and may even offer some nice alternatives to counting the maximum concurrent users. But beware of the "platform change" -- it is officially dead. No sales weasel is supposed to be charging it anymore. Not that a little thing like policy stops them from trying.