So something that you can do with PDKs is add your own custom standard cell and tell the EDA tools to use them. This is actually pretty smart, this way you can use most of the foundry cells (which have been extensively validated) and focus on things like this "magic multiplier", that you will have to manually validate. This also makes porting across tech nodes easier if you manage only a handful of custom cells versus a completely custom design.

(I have my guesses as to what that is, but I admittedly don't know enough about that particular part of the field to give anything but a guess).