Are you working with progeCAD 2013?
In our tests the behavior of the PSLTSCALE and the LTSCALE variables is the same that AutoCAD.
If you turn OFF the PSLTSCALE variable the Scale of the linetype depends on the CUSTOM SCALE value of the single Viewports.
If you turn ON the PSLTSCALE variable all viewports show the same scale of the linetype, and that depends on the global LTSCALE value.
progeCAD support, tips and troubleshooting forum. progeCAD works very similar to some versions of AutoCAD. Moderated.