Use RC Notation to copy formula from different sheet while maintaining relative references

[ianm101]

Hello,
I am trying to copy a formula from another sheet ("SCE_Tables") to a central sheet ("Main"). "SCE_Tables" holds reference tables that I am copying over to main, based on selections from a form that the user fills out.

The formula in "SCE_Tables", uses RC-notation to subtract values from columns 2 to the left ('Prebill'), and 1 to the left ('Post BESS Bill') of the cells in the 'BESS Savings' column:
In the highlighted cell below:

=RC[-2]-RC[-1]

. This cell is at Row 15, Column 6

The issue arises when I try to fill the "Main" sheet range with these tables. The "Main" sheet range where these tables go have the same format as the reference tables:
The highlighted cell below (on the "Main" sheet), is at Row 21, Column 18. The formula in this cell is:

=R[-6]C[-14]-R[-6]C[-13]

The RC reference that is copied over to the "Main" sheet converts the RC reference back to that in the "SCE_Tables" sheet, resulting in the formula trying to calculate

(R15, C4) - (R15, C5)

on the main sheet, when my desired formula is:

(R21, C16) - (R21, C15)

Is there a way I dynamically create a formula that calculates the difference between the cells 2 to the left and 1 to the left of the cell in the "Main" sheet?