The way I would have set up the worksheet would have been something like
the following:

H27: 0 or 1 (the flag that says "Rental Tax" is applicable?)

J29: =IF(H270,"Rental Tax","")
K29: =IF(H270,R27,C12*R29,C11,"")

or whatever the formula is supposed to be (=R27,C12*R29,C11 does not look
like a valid formula to me).
--
Regards,
Bill Renaud