I think you're doing it the hard way! Changing the pressure down to 8 psi to pour would be a huge pain for me. I have several taps, and I'd have to open the kegerator, reach way in the back and get on my knees to reach the regulator, close the co2 to that keg, purge it, crawl back into the kegger to reset the regulator and then do the same if I want a different beer?!? Then, do it in reverse to turn it back up?!?! No way!
Balance the system once, and keep it at 12 psi always. That's what I do! It's super easy, and allows multiple kegs at once to be carbonating, serving, lagering, etc. It's a no brainer.