Good vet.
I wouldn't totally agree that below 100 means no shunt though. While there is "probably" no shunt, a dog with bile acids of 51 could still have one. If that is the postprandial number, Ellie's came back about the same and her vet wanted it rechecked it one month after changing to a low protein diet and supplementing.
The 21% protein for an asymptomatic dog isn't a big deal. The problem is the type of protein may not be the bet for him. But then we get into how far does the vet want you to take this and should his diet be watched extremely closely, etc.