Main weight saving...
...in your model of Lunar-extracted propellants is not that they are cryogenic vs hypergolic, but that they are Lunar-sourced rather than carried-all-the-way-there-and-all-the-way-back.
If you knew there was ample fuel waiting for you on the Moon, you wouldn't need to carry it all the way there, including launch to Earth escape velocity. The Saturn V could have been half the size if there was refuelling station waiting on the Moon.