Is there any way to handle changing data in Power Query or using DAX

I have a scenario where one column A in the dataset will change during refresh.

Let us say the value is 100 and after refresh it is 150.

Also, I have some calculations built using A for monthly revenue calculations.

Rev Jan= 100 - 50 = 50

The value of Rev Jan(50) should not change after the refresh even the value of A changes to 150.

Is this achievable in Power Query or DAX or how can we handle such a scenario in Power BI?