I find it interesting that you all are saying the 1 year and the 3 year are the exact same med & dosage..no difference.
Read this article in Alabama where a vet, Dr. Karen Sheppard, says they are not the same:
Pets in Alabama may get 3-year rabies shot | al.com
Is it possible, that they have changes since 2009 (when this article was originally written; although it was updated in 2010)?
Where is a resource that states the med/dosage for 1 year v. 3 year to compare?