I think percentages depend on your dog. Some dogs really do well on higher protein, on the other hand some are not able to tolerate it. My Taycie never was able to tolerate super high protein, she always ended up with a very upset stomach.
As for Pancreatitis, feeding high fat food defiantly can lead to possible bout of pancreatitis. I honestly never felt comfortable feeding something overly high in fat to a breed that has such issues with Pancreatitis. There are many other things that contribute to Pancreatitis like feeding table scraps, getting into something they shouldn't etc....
For me, if bloodwork is coming back ok you are probably ok. Most importantly your vet needs to be aware of what you are feeding. I know many on here feed TOTW and really like it. If your vet is comfortable on what you are feeding and he is thriving on it then there is no reason to switch
