^ @ApolloCrowe beat me to it. That's definitely the big issue with higher flute counts.
Depending on what software you're using for your CAM planning, you can work around that limitation a bit by using so-called 'adaptive' tool-path strategies, which Al Whatmough of Autodesk does a good job explaining in this video:
Because the tool-path strategy is always working to side-mill and not plough-cut, and it frequently is working in "swipes" at the material, it provides an opportunity for chips to be evacuated between passes into fresh material.
A spiral-from-edge path would be a good "next-best" candidate for this kind of thing, IF you've got adequate chip clearing from compressed air or coolant (which you probably don't on a Nomad or So3...)
The other thing to consider is whether or not the updated feed/speed rates for the number of flutes you're trying to use still falls within the recommended cutter surface-speed for the cutter and material combination. If it doesn't, you may be going too slow or too fast in that regard, so it's definitely a multi-variable joyride X-)
You want just the right chips, not too big or too small, not generated too quickly or too slowly, not re-cut by the cutters... and you don't want to overdrive your spindle or your linear axis motors, or burnish the part and wear out your tooling.