I have a bunch of Tiberius 8.0/9.0 and 8.1/9.1 markers. I even have a 8.0 with the 8.1 upgrade kit. So, my question is why the 8.0 mags do not seat and latch in the 8.1 and vice versa. Is this just a fluke on my end or is there a reason for the incompatibility that I have not noticed. I would expect that the 8.1 should fit and latch in the T8.0 marker. That would be the reason for the upgrade kit. However, I have not been able to get the 8.0 mags to latch in the 8.1 marker or the reverse, including the T8.0 with the upgrade kit. What am I missing?