When I tried it actually went back to 30 fpsHi
Spot on. Once you disable the mod after rebooting with it enabled, the 60fps stays stuck on as it enables it through boot and not the mod menu (even though you get that message where it does a reload of assets in game). The game then thinks you are using no mods so the achievements unlock.
I've been doing it this way and enjoying 4k60 with cheeves popping fine the last few days..