My headcount planning app currently uploads a headcount report on a monthly basis and the forecast basically rolls forward after every new month and the only way I can compare changes over months is to take a snapshot and change the switchover month.

How should I approach making this update since it seems like I would have to rework the entire application and add a version to every metric? My current thought is that a budget version is tied to a specific months load, so I can do a mapping for load month → version but does that work?

Example:

Current monthly data by load month

Expected Result if I want to use June load month for BoD Version. The data from Jul onwards would only use data up to the June load and not use anything beyond that. 
 

Any ideas would be appreciated.

Thank you!