New hires to existing employees side by side comparison

In oracle epbcs workforce, I have a new hire requisition H1 for $5000/month salary for a given entity in Jan'25 in my frozen budget.

I keep also a working forecast with "existing employees" actualized and "new requisitions" forecasted.

Actuals come in. Employee A is who was hired for the H1 position and actually makes $4,800 per month (hired at a lower rate). so I run the Associate Employee rule to reconcile the headcount.

My forecast for Jan shows $4,800 and my budget for Jan shows $5,000. So at top level, I have a favorable $200. I have a budget surplus.

In this simple example, since I have just one hire, I know that this favorable $200 will keep accruing every month due to the salary advantage. Now, If I had 10 new hires instead of one, with different salaries, I could see an overall $300 favorable budget surplus for Jan overall, but it would be very difficult to tell the story, for example, that for employee A, I am spending $200 less that I initially budgeted, B is consuming $50 more, and such. This is because the relationship H1 to employee A is lost to the end after the headcount