That fake plywood, usual stuff from B&Q is almost impossible to cut without feathering, even using a new cutter in a 24000 router.
Ive even had it show feathering using a power fretsaw and that useually cuts very clean!
Also a ball cutter is not the best to cut wood with, better to get a single edge cutter and up the speed if you can.
If you want to use the cheap(not these days) B&Q variety you can do it by varnishing both sides the day before, I used to do this when I built model boats, gives a very clean cut although costs for the varnish!

Peter