Not sure, but I have seen recommended stepovers of 5%-8% (0.0125" - 0.020" for your tool) for Ball End mills doing contouring work. I think 30% stepover is a bit too much for this tool. The 2 numbers I stated are well within the tip radius (0.03125") of your tool.
Not a pro, but it makes sense you should not exceed the radius of the tool for contouring work.
Thanks, that makes sense. I was expecting that the software would calculate the stepover based on the diameter of the ball end.
I can’t help with Millmage but in Aspire, the % stepover on tapered bits is related to the tip diameter (2X tip radius) and for end mills with no taper tip and bit are same diameter. So from your example with a tip radius of 0.03125 and stepover of 30% I would get 0.01875 on my software.
Every software package has its own set of rules. 
Ball end and flat-tip taper mills are the only bits that would be able to work this way, and doing so causes other problems - There are numerous fields in the software that work on “percentage of bit radius”. We initially tried making it work the way you suggest, but it got confusing, and broke a bunch of things.
