Using FMJ at first is supposed to polish out imperfections in the feed ramp, etc. & since they are easier to feed than hollow points, gives your pistol time for the parts to "mate" before trying the more difficult JHPs. That may be why Kimber says to cycle 500 rounds before contacting them about feeding problems.
As for a true "Break-In", I have read that some 'high end' manufacturers say you should not field strip, clean or lube their pistol until you have fired 500 rounds. So, other than that, I consider the first few hundred rounds as a 'get acquainted' period.