I just switched Bella from NB to Orijen and fortunately the boutique I am now purchasing her dog food from the owner is absolutely anal retentive about dog food research as his clients are (he has dogs too). So while I was talking to him, I posed the question about the higher protein amounts and he mentioned that a University in (I think) South GA or somewhere did a 5 yr study to see if higher protein levels did cause kidney issues in dogs. Anyway he went on to say that the research learned from that study is being passed along to the veterinary schools. I wish I could remember everything he said but I was there for over an hour talking about dog food
so I'm afraid I'm slightly off on some of the details about location and stuff.
I hope that helps. Regardless, the biggest thing is if your dog doesn't have a problem with the food then I would stick it.