Control is a critical part of GPS on a job site. It should not change except with great forthought and checking. The most likely reason for it to change is on a job that requires multiple base setups.
Apps doing alignment can upload to AGTEK Access projects and store a control file with a description. Apps that can use alignment data can check AGTEK Access for control files when none is present in their file.
ESW Files
Change Orders Phases
Control Files