I've had previous systems plumbed up with a t fitting after the membrane and before the di so I could fill up 5 gal water jugs for house drinking water. Worked great.
Current system is not plumbed this way due to use of pressure switches and booster pump. Currently looking at auto flush kits for a mixing station build to help reduce tds creep between the system turning on and off on it's own randomly to keep containers topped off
Here is my 6 stage. Actually just upgrade to this from my 4 stage spectrapure 90gpd. So far I most happy about the reduced waste water and increased water production. Triple inline tds meter is pretty awesome as well