Static Past Period cost and Dynamic Current Period Cost Calculation

Hello Community

We have a dashboard that allows calculations of a set of costs. The user can also assing the cost value using a paramater/whatif slicer. The users can see the budget performance and play around the cost with what if . They can also select periods from a slicer to see individaul quarters performance according to the variable "cost" selected from the slicer.

We would like to upgrade this dashboard for pre set costs for each period and a what if analysis for the current period while the user can select multiple periods at the same time from the slicer.

Exp: Q2 2022 and Q1 2022 costs are pre set and are stored in a table. Q3 cost is to be assigned from a what if slicer

Visual that shows the budget cost for any  selected period

This sitiation in the future will of course change and along with Q1 and Q2, Q3 cost will be set a specific number and the Q4 cost will become a what if scenario while the user will have the option to select any or all periods from a slicer.

The only valid option I could think of is to calculate the past periods from a lookup table and simply remove the current period from the slicer. Create a seperate page for the current period what if scenario. 

Any desing ideas would be much appricated

thanks