5.9 stroker build

Their "max lift" specs depend on installed height. If a given spring is installed at 1.900" it'll have a shorter max allowable lift than if it was install at 1.950". Since their inconsistent documentation mentions two different installed heights, that's probably why you see two different max lift numbers. The max lift number is a bit irrelevant anyway. That's just a calculated number based on the coil bind height + clearance and installed height.

I'm curious what the installed height of your springs actually are. I'd bet they're 1.950" ± .010" or so. Post up that number when you get a chance to measure.