Dynamic Calculations inside a nested member

Hello,

I am new to building cubes in OS, I am attempting to build a calculated column based on data from two other columns, I have created a nested member which correctly brings in all the data. When I attempt do use GetDataCell I return errors that it cannot find my named Column.

In the screenshot you can see the member filters (highlighted are the same rows)

Here you can see the output when I run the cube view.

Please let me know if I cannot reference in this way and how I may solve the problem