It depends on how much you want to change.
The calculation formula is written in the ASM program.
You can do as much as you can change items in the formula,
If you want to change the calculation formula itself, you have to rewrite the ASM program itself.
As a kaitou-patch I made, I rewrite the whole hit ratio calculation formula,
I am making a hit rate correction by difficulty level.
With the ROM editor, we can not support that far.
If you want to specify it finely, you should write a program.
Also, since multiplication and division are realized by bit shifting, * 2 and * 4 can be done, but * 3 etc can not be supported.
It is expected to be quite restrictive.
Therefore, it is doubtful how much it is necessary to support with the tool.