I Wana add this isn’t an absolute rule I’d say. If you have any deficiency issues it is probably best to keep feeding atleast some. Once you start that water only there basically no going back. After a week, if it starts looking really starved you won’t have time to correct it. I guess feeding till the end could be considered an insurance of sorts. I’ve done it all the way until end, and while I found it perfectly fine to smoke I feel it tasted better and is smoother with doing the water only flush last 2 weeks. I use technaflora nutrients, and while I don’t add nutrition, I do use sugar daddy the last week only once at 40ml per gallon. It’s a carbo load to help stimulate microbes to consume any remaining nutrients. I’ve also tried leaving this out and found sub par results.
Also if you do light feeds, or your watering every day your likely feeding alot more than I do. I water every 3 days, nutrition every other water at 2/3 strength, in 5 gallon fabric.