Hi,
Wow, sounds very confusing! Anyway, if the Dr uses the same tax ID# for both locations then it sounds to me like he would need a Type I NPI for himself, but a Type II NPI for his group name & tax ID#. Even if his group name is his own personal name, since he is billing under a tax ID# he should get a group (Type II) NPI.
Then you should bill using the individual NPI to identify the provider, but the group NPI to identify where (and under what tax ID#) payment is to be made.
If the provider is listed with Medicare as a group, then he would need a group NPI. If he is listed as just an individual doc then he should only need the individual NPI.
I'm surprised that calling Medicare hasn't straightened this out. Usually they are good at telling you exactly what the problem is so that you can rectify it.
I hope this info was helpful. If not, and you have any other info to give me, respond and we will try to help you get to the bottom of it!
Good luck!
Michele