If you run FCOM with Immersive Gameplay, some NPCs would have very low health (20 hp). All this patch does is bring the FCOM units' health in line with IG. You can place this wherever and it should work, UNLESS you are also using my Minutemen NCR Overhaul FCOM patch, in which case you need to make sure this patch is loaded ABOVE my Minutemen NCR Overhaul patch or else you wont see the NCR gear on your MM troops.