Absolutely in the last bit water uptake goes down. I see peeps flushing hard then and probably the worst time to be flooding a soil medium IMO.
Dude! Thanks for that link pretty cool info> PeAcE!Wade through this link you'll learn a lot.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC439254/
If you have to flush your plants/medium at the end to remove excess nutes you've overfed. Just my opinion.