Copying formula down with horizontal source data

[NDF]

I am trying to copy a formula in B38, down to B36
My formula needs to refer to data in of cells in a horizontal succession, G1, H1,, I1...etc
Copying my formula down from B38 causes the formula to refer to G1, then G2, G3... instead of G1, H1, I1 ...
The exact formula in B38 is:
=$B$3*(G3*(1-$D$13))
Where G3 should advance to H3, when I drag to copy the formula from B38 to B39. Instead, G3 advances to G4.

Thank you.

[mrice]

Try

=$B$3*(INDIRECT("R3C" & CELL("row",B38)-31,FALSE)*(1-$D$13))

[NDF]

Thank you very much.