IMO, IRCC is sticking to 3000 as a ballpark figure and twice a month draws (mostly on wednesdays), I do not think they are targetting a specific score for a draw, if the number of people in pool having high scores is more, the CRS goes up. So the CRS is more a matter of how many people enter pool before each draw. If they issue 6000 ITA each month for 12 months, they are closer to their desired target. Just pray that number of people entering pool with higher scores get lesser by each draw so that the score falls. And when it comes to a gap of 2 or 3 weeks, it has got to do more with how many wednesdays are there in a month, for instance feb was a shorter month so we had draws with a gap of 2 weeks.