Lowering Protein In Food

[RDandSQ]

9 year old 75 pound dog's labwork showed dilute urine specific gravity (1.007) and slightly high creatinine (1.7 vs. range of 0.5 - 1.6 mg/dL). BUN mid range (21 mg/dL) and Phosphorus low-mid range (3.0 vs range of 2.5 - 6.0 mg/dL). The vet suggested going to a Senior Food to get a bit less protein. He was more concerned about the urine than the creatinine. But I worry about kidney issues.

My dog is on Ziwipeak dyhydrated raw food (it's not raw once dyhydrated) with "quality" protein and no grains etc. It's pretty much all meat. He get's 6 scoops per day, with fish oil and some other supplements (Missing Link and Sea Meal). I was focused on the percent protein (36%), but not on the total quantity.

Doing the math it seems he's been getting 122 gm protein per day for the last year or so. I now understand the guideline for older dogs is about 2 gms/ per kg (or about 1 gm/ pound), which is slightly more than for adult dogs. Based on this he should be getting about 75 gms/day.

I'm thinking rather than going to a commercial senior dog food with grains and other things, why not just give him less Ziwipeak and augment with vegetables? I was thinking of going down to 4 scoops (about 80 gm) per day, and giving him pumpkin, sweet potato, or cauliflower or a combination to make sure he gets the same amount of food he is used to.

Does that make sense?