Referring to a Sub-Field on Calculated Field Pivot Table Column?

Hello people:

I am currently looking forward into adding a Calculated Field Column into an existing pivot table, the issue I am having is that I see the Table fields to enter them on the new calculated column formula, but is it possible to list or see the sub-fields? For example one Field has two subfields, and I need to multiply each subfield by a different number.

Thanks very much!

I have been researching without success, but I am thinking about alternative solutions:

a) Is it possible to add a sub-field as as a main field list for a pivot table?

b) Is it possible to a add a a calculated column on a pivot table based on cell name or any custom name?

Thanks!