One of the specialists I use always says to treat the pup, not the labs. Of course you don't want them to have a very low albumin. Maybe since he is feeling so much better it will start to go up.
I home cooked for Cookie. I did a consult with a vet nutritionist and she was on that diet from 2011 when she was diagnosed until March 2017 when she passed. It was sweet potatoes and tilapia plus supplements. If you have time to do that, I have to say it was wonderful for her. You could check this website out for a free recipe (as long as your vet approves it) :
https://secure.balanceit.com/tools/ez2/index.php?