The difference between the previous tests & this latest one is not a bug jump by any means, I would say at this point he is fairly "stable", meaning gradual changes.
Regarding the fur pulling - did this start after a specific event? ie change of food, adding the coconut, moving, change in household dynamics, new detergent, etc ?
It's usually displayed as a self stress reliever or as an intolerance reaction to something either in the environment or that they're ingesting or lacking as in Vit B deficient.
Fur pulling can also be a symptom of HyperThyroidism - for that diagnosis you would need a T4 (Thyroxine) blood test add-on unless it was done already within the Geriatric panel.
I've not had any personal experience with fur pulling.
Personally I would start the Azodyl, Duffy had good results from that.
I would either have the food discussion with the vet if you are comfortable with this one & want to stay or find someone more willing to work with you.
If you stay with this vet you can always tell them you are not willing to further compromise the health of Sam's kidneys by feeding him a food that is almost completely devoid of the moisture his body & kidneys so desperately need to function normally that you will not discuss diet with them.
Avoid biting when a simple growl will do
The Spirit Lives As Long As Someone Who Lives Remembers You - Navaho Saying
Vindication ~ For all those pets who became sick or lost their lives from tainted pet food