Formula from PowerBi to PowerPivot

[marsclone]

I have a formula in PowerBi that I would like to use in PowerPivot.

Only in PowerPivot, selectedvalue is not available and I think I should use if(hasonevalue)?
However, I get the message:

In the Switch function, comparing values of type True/False with values of type Number is not supported. Consider using the Value or Format function to convert one of the values.

How should I modify the formula?

Thanks!

PowerBi formula:

Total IST c =

if(AND([IfFiltered]=true(),[CheckHoofd?]=1),

BLANK(),

SWITCH(TRUE(),

SELECTEDVALUE(Hoofd[Subtotal?])=0,[Total IST a],

SELECTEDVALUE(Hoofd[Subtotal?])=1,[Total IST b]))

PowerPivot formula:

Total IST c:=if(AND([IfFiltered]=true();[CheckHoofd?]=1);
BLANK();
SWITCH(TRUE();
IF(HASONEVALUE(Hoofd[Subtotal?]);0;[Total IST a]);
IF(HASONEVALUE(Hoofd[Subtotal?]);1;[Total IST b])
))