Yeah, I assumed so, but I realize there are a lot of aspects about the settings that I don't understand. fBlock didn't make any difference either, but I finally figured it out by brute force testing. Realized the vanilla test profile was still using modified ini files and without them object LODs worked fine. Systematically deleted chunks of settings until I identified the .ini setting that caused it - uLockedObjectMapLOD=32 - which I added to prevent trees on the world map. Unsure of why that prevented all object LODs outside of the map, but at least the issue is resolved.
Thanks again for your time Sheson!