I think they eat into the eleventh hour. In soil, it is easy to see them “stop taking water”. In coco, this could be observed in high Ppm run-off .
Not certain about that product in particular , however; some flushing products simply knock the ph so far out of whack that the plant cannot relate to the soil. It somewhat arrests uptake. As there is little nutritional ballast within coco by nature, simply watering at the end would have similar effect.
I find my plants are growing and putting on weight right through into the harvest window. I don’t want to rob myself, and continue to feed until the plants tell me they are done.
Afterwards, my high Ph tap water will knock them dead in a week.
For myself, advertised finishing times are simply that. The number gets you to buy the seed. Tons of white hair and barely a cloud to the heads does not mean harvest time to me ,,,and it says 8 weeks ?
Nah, I peak in week 7, top out at 12-1400 Ppm. Only N from the Clamag after that.
If that product is a dead stop, when utilizing in coco , 4-5 days should do it.
I know some people are backing off softer and sooner. However , I see my buds increasing in size dramatically, long after heads are cloudy(50-55 days). Those warty grampa buds don’t seem to shrink up like those early pulls.
Science time! Do you have a couple to play with? Can you start one before the others? Or delay one, and flush it later than others. ?
Common sense would dictate disregarding Jewels and reading the bottle instructions. The answer lies somewhere in between,