Alright
I haven't had much luck with these calculators from different websites, Take your pick, american machinest, Gwizard.. so on

The machine I use reads in IPR along with RPM

To have a nice finish I've come to such conclusions as

For example with 6061 Aluminum
cutting through a thickness of .135" with one pass for nice finish works to
850 IPM 14K RPM single flute. which give me an IPR of .061

cutting through a thickness of .350 with one pass, milling out ward
same.. one pass for nice finish works out to
2800 IPM 14K RPM single flute. which gives me an IPR of .2

My question.. Are these IPM numbers irregular? Are the RPMs irregular. I'm trying to see if I'm doing something wrong or missing something.

Thank You!