Function calculate with true/false expression is not allowed

Hi,

I have a simple formula where i want calculations based on text string selection in a slicer. Below formula is what i am using but returns below error message. Appreciate any help!

"A function 'CALCULATE' has been used in a True/False expression that is used as a table filter expression. This is not allowed." 

POS TY = IF(SELECTEDVALUE('POS CY'[Slicer])={"L52W"},Calculate(SUM('POS'[Values]),'POS CY'[Slicer] IN {"L52W"},IF(SELECTEDVALUE('POS CY'[Slicer])={"L4W"},Calculate(SUM('POS'[Values]),'POS CY'[Slicer] IN {"4W"})),IF(SELECTEDVALUE('POS CY'[Slicer])={"L13W"},Calculate(SUM('POS'[Values]),'POS CY'[Slicer] IN {"L13W"}))))