Well 600 is 10% of 6000 which is about right as a ball park figure of what u should have if u fly under the ifr on a regular basis.
It is hard to start and stop a stopwatch every time you get in or out of cloud. Personally i find it unfair that an ifr instructor can't log any if other than what he is hand flying although he could be in the poo with a student for 3 h, which is what they do in the states, which is more aligned with ICAO regulation, what Australia used to do ! !