as long as the plant being flushed early doesn't nosedive during that time ... if the canopy retains its color etc..
flushing isn't neccessary, anyway. it's anecdotal urban myth. maybe, if you have major toxicities going on, it is a net-positive action at end.
water res? you only need a 1-2 day flush anyway. i bet it handles that just fine wihtout impeding photosynthesis of the other plants.