Standard threads in nx5 - "Radial Engage"

I am trying to understand how the standard threads are setup in nx5. I may need to add some company standard threaded holes. Something I don't quite understand is the "Radial Engage" values you can select from the hole dialog box. They don't seem to correspond directly to the percent of thread often used for thread standards. It does seem to have the same effect of changing the tap drill size. Can anyone shead some additional light on this parameter?





Thanks

I would like to know the answer as well.