I took the tap file and checked it with another program and it seems to give me the same results as Onecnc's job sheet. So it must be correct.
I must have misjudged the parameters I was using that I spoke about above, because I cannot reproduce that type of discrepancy again.
Also, I guess that maybe I am just expecting it to take longer because of the way I used to cut these molds. Beforehand, I didn't dare use as large of a cutter as I am now, because I was fearful of leaving too much material in unknown areas. Gotta hand it to those Onecnc guys, the Rest Robot is a cool feature and takes some getting accustomed to.