Not unlocking - Updated

I don't know what's going on, but I am now due 2 achievements in this game, as I have met the criteria and neither have popped:

Half Mill Club
Higher Than Most

In all fairness to Yazite, he was very helpful and we tried a few things but to no avail.

Anyone else having the same problems? Or does anyone have any solutions?

YOu need to be host and it needs to be done in the first coop song after u load the game up. If you retry, go to dashboard and reload the game before doing so