Faultline, THC definitely can vary on the same plants even from the same clone mother. Especially if the harvest time varies. I use a microscope to verify that at least 5% of the trichomes have clearly turned brown or amber. I do this to make sure the THC is ready. If you harvest the same plant earlier it will definitely have less THC.
It may have more CBDs though. Or possibly the CBDs show up before the THC so folks that just want the CBD effect can avoid the THC high. Not sure on all this CBD stuff but willing to listen. I am wondering if folks know of strains that are high in THC and CBDs. I like the effects of both.