In the example below, operation with 3/5 convertor ON, can display a difference in material removal between tool path simulation and Machine simulation. The difference can be seen in the video below. Essentially, with RTCP OFF, the tool path simulation does not show any clash issues, as opposed to the machine simulation on the same operation. This can be easily misinterpreted as an issue. With 3/5 convertor active, it is better to have the RTCP option  checked ON on the 5-axis machine's NC Programming tab ( shown in the video).