Project Rules allow you to set Revision settings as well as set an archive schedule for Projects.
Here you can select any number of Project Statuses for which you would like a Revision to be created for when the the Project Status is changed to them.
This option allows you to choose how many of these Revisions to maintain vs. all Revisions. This can help you save storage space for Projects by eliminating any of these "non-Change Order related" Revisions you may not need to keep.