Flushing is for toilets. There is no scientific proof that flushing does anything positive for your plant, UNLESS, a grower is killing his plant with too many nutrients/ferts. Flushing will stress your plant (even if you think it needs it) at a time when it doesn't need to be stressed, it needs to be fed.
Proper curing is the answer to an excellent, finished product. I don't even like when too much water drains out of the bottom of my grow bags because precious food is going out the back door. I feed all the way to the end because it's obvious the plants begin to consume themselves during the final phases of flowering (Leaves turn yellow/dry up and fall off), which BTW, is not a natural path for an MJ plant. Some growers swear they can keep their leaves green up to chop, chop.