Feature Outline Masks Calculation coordinate system doesn't recalc in model builder

I've built a simple model using Feature Outline Masks from the Cartography toolset. I've noticed that the Calculation coordinate system parameter doesn't recalculate in a new MXD with a different projection. It keeps the same projection as the mxd I built it in or it stays empty if built in Catalog. It's important that the masks are created with the same projection as the MXD. Setting Calculation coordinate system as a parameter is an option, but not practical as the model is used repeatedly. Has anyone come across this and found a possible solution?

Also, I've tried using Calculate Central Meridian and Parallels and Calculate UTM zone to make an output that I could plug into the Calculation coordinate system parameter. The problem there is that the Calculate Central Meridian and Parallels has the correct UTM zone but the central meridian is off. Calculate UTM zone has the correct central meridian, but the UTM zone is wrong (it ends up with a Q, M, or some other letter). The feature classes in the TOC only have a geographic coordinate system. It's only the MXD that has the projected coordinate system set. Either way, the masks don't match up correctly when I run my model against Feature Outline Masks. Is there a way to get the spatial reference from the MXD programmatically?

Any help would be greatly appreciated!!