Find And Replace Certain Characters In Formula?

I basically want to find and replace certain characters in a formula, but the formula is quite intricate so I will give some background to the problem first:

I have a complex spread sheet which is used to check if a data array matches another data array (both data arrays are different sizes). One array has a set of parameters for a variable and the other array has the variables and the actual values for each variable. I have a section with the following formulas to check if the actual value (C121&D121) matches the parameters ($A$9:$A$108, $B$9:$B$108) & ($C$9:$C$108, $D$9:$D$108)

I have the following formula in cell AB121:
=(C121=INDEX($B$9:$B$108,ROW(101:101)-INT(ROW(100:100)/$D$1)*$D$1))

In cell AC121:
=(D121=INDEX($D$9:$D$108,ROW(101:101)-INT(ROW(100:100)/$D$1)*$D$1))

And have similar formulas from AD121 to AY121. I mention this to point out that excel regards this as an inconsistent formula, I haven't copied and pasted it over, I have had to re-enter it in each cell adjusting the parameter sections.

The problem I have is that currently this is set up to check through a data set and wrap around every 100 rows ('100' Entered in $D$1) but I want to adjust the formula when there is a different amount of rows to check. So basically the only way I can think to be able to do this is to have a formula or something in VBA (which I have very low level experience with) to be able to go into the formula and change certain characters within the formula. For example, if I wanted to check 95 rows instead of 100, it would need to have 95 in $D$1, which I enter in manually, but then how to go in and replace (101:101)-INT(ROW(100:100) with (96:96)-INT(ROW(95:95) in 2 sections in the 1 formula then do the same with the inconsistent formula from AC121:AY121?