Medicare rules are that you are not reimbursed on date of E&M so congratulations if it is working for you - I have been screwed in the past so given up. The other thing is that since pharmacies are so into giving immunizations anyway that I just developed a rapport with local ones and get a report when one is given and my staff enter it in Health Maintenance.
Interesting thing about Shingles vaccine is that the reason there is no vaccine code for administering is that it is a Medicare D benefit which we can't bill. I am surprised you get even the cost of the vaccine as it should not pay under Part B.