Personally, if I'm not running the cutter all that deep, only a relatively small amount of the flute near the end gets worn. So I figure why spoil all that flute that hasn't even tasted iron yet?
Regrinding the flute also erodes the rake angle created between the inside face of the flute relative to the land. The closer you get to the cutter axis, the less positive the flute becomes.
The gullet gets shallower and has more difficulty with expelling the chip in softer materials.
So, to preserve the coating and get an extra life or two out of the cutter, I simply cut it off at the wear depth with a narrow diamond wheel. Then, back off the ends of the teeth a little and then its back to the mill.