That function depend on
a) crystal frequency
b) clock use (1-2-4-6-12)of particular derivative
c) instruction cycle use by particular derivative.

Re c) I have found that even the number of instruction cycles for certain fast derivatives do not follow the old norm e.g. Cygnal F12x use 8 instead of 4 instruction cycles for a DIV.

So, I will guarantee you that any 'canned' delay routine will fail under some circumstances.

Write your own in assembler it takes 5 min to write and 15 min to verify.

Merry Christmas

Erik