IMO, those time-released nutes are burned up waaaaay before harvest-time, and not an issue. There's barely any in there anyway, just look at those numbers .021-.014-.010 or something like that, which is like 1/50th strength, if what we normally feed them. What I've found, that MG soils, amended with perlite, will perform as well as just about any soil out there, including Fox Farms. I tested it, for those who don't remember...."""
https://www.rollitup.org/newbie-central/373397-test-progress-miracle-grow-soil.html """...and the MG soil came out on top, after I added 20-25% perlite.
Personally, I think the problem is that all the new guys are 'nute happy', thinking they MUST feed their plants, to give them a boost, and end up fucking 'em up, in the process, especially with the 'hot' soils. 75%+ of the grows I see here, don't even need any nutes during veg, but still, they add 'em anyway,lol when in reallity, they didn't need anything til 12/12 started. And, I'm not even going to mention all the problems I see with watering habits...