System 6T hitting limit on turret change

I have a pratt and whitney system 6T lathe, when I do a tool change it sometimes shifts the z axis forward, sometimes not at all and it most of the time shifts it backward into the z axis limit. It appears to be related to the z offset of the tool at the turret position, so it offsets the axis at every turret position.

Is there away to stop this? I have set my tools change position out a couple of inches to avoid hitting the limit but now I have a longer drill and will need to adjust it even more.

Thanks
Andy