Help with What-if Parameter

Situation

I am trying to use a What-if parameter to shrink inventory by a certain percentage each month. This is so we can account for things like breakage or lost inventory. I have the parameter working, whereby it will apply a selected percentage and decrease the inventory, but it is seemingly does it uniformly across all months.

What I need:

I need this parameter to compound. Meaning, I need to reduce January inventory by .1% and then I need that take that new inventory number and use it as the inventory for February and reduce it by .1% for March, and so on throughout the year. Is there a way to make this compound in this way?

Here is the parameter currently:

Inventory With Variable Shrink Adjustment = CALCULATE(SUM('2019_Inventory and LE'[Actual and LE])) - CALCULATE(SUM('2019_Inventory and LE'[Actual and LE])) * CALCULATE(SUM(Shrink[Shrink]))

Thanks!