Scrip Manager cumulatively calculates tuition credits and does not use a credit counter. The unposted amount is simply the users total credit earned less total credit posted. You might encounter a time when the unposted tuition credit does not equal the sum of credits earned for each order since the last credit posting. The most frequent reason is due to a change in a an order prior to the last posting.
Jun 1st: Order # 1 entered with a credit earned of $20.
Jun 30th: Admin posts this credit to the user's account and the unposted amount is now back to $0.
July 1st: Order #2 entered with a credit earned of $10. (Note: at this time the unposted amount will show $10)
July 5th: Admin modifies order #1 and adds a certificate increasing that order's tuition credit to $25. (Note: at this time the unposted amount will show $15 because a $5 credit from order #1 has not been posted. Likewise if order #1 is reduced by $5, then the unposted amount will show $5 because your last posting of $20 on Jun 30th would now be an over post.)
Remember Scrip Manager cumulatively calculates tuition credits. Therefore if you over or under post at a certain time, over the life of your program the credits will reconcile.