Power Pivot does not add the closing parenthesis of functions or automatically match parentheses.You should make sure that each function is syntactically correct or you cannot save or use the formula.
When you add the measure, the formula is evaluated for each cell in the Values area of the Pivot Table.
Because a result is created for each combination of row and column headers, the result for the measure can be different in each cell.
You can nest functions, meaning that you use the results from one function as an argument of another function.
You can nest up to 64 levels of functions in calculated columns.
If you want to place calculated results in a different area of a Pivot Table, use a calculated column instead.