Converting milliseconds to frequency

[RussMartin]

I may not be understanding something here.

For the basic math, I would have said:

rpm=60000/z

where z is in milliseconds.

That would work, but that kind of division in PBP would take up a lot more processing time than the IF...THEN statements above.

My question is: Why would doing that single division take longer than going through multiple IF...THEN statements (40-something of them in the example) until one is found where the condition is satisfied?

Thanks to whomever clarifies this for me!