Correct PeopleSoft Object for "Project" PO

USING: PeopleSoft FS/SCM 9.2, Tools 8.61

TLDR: what's the correct setup of PeopleSoft FS/SCM to represent a large contract associated with a sizeable project (e.g., building a building), which will change many times, and will be paid over a long period of time (but not in any standard way).

Representing the above as a Purchase Order doesn't work well:

• It stays open for a very long period of time
• There's no easy way to see (in the data for reporting) how it's changed over time - you have change orders, but PeopleSoft only persists the current state of the PO