I believe the vaccines are the SAME. It is the laws in the state that vary.
I would be DEMANDING that the vaccination certificate be changed to reflect THREE YEARS. Arm yourself with the state, county, and local laws/ordinances. Threaten to take your business elsewhere.
If they refuse to alter the certificate, see if you can find a holistic veterinarian that will. I know in my state the law states, three years
or the date listed on the certificate. I raised holy hell when I found out my veterinarian automatically puts TWO year expiration dates on their vaccination certificate. According to the law, I was required to revaccinate a year early even though the LAW only requires every three years. My vet eventually changed the certificate dates and apologized.
The Rabies Challenge Fund is a great resource. They are very helpful, even for support/advice!
http://www.rabieschallengefund.org/