This has gotten well away from the original question. Lets clarify the certification issues and put that issue to an end.

MOST states do not require an agency affiliation for certification at the Basic (EMT-B) level, SOME US states do require that you either have agency affiliation prior to certification, by the end of the first certification period, or some time period in between. These rules change frequently, check your state for the current rules where you live.

There is only one national certification organization for EMS, National Registry of Emergency Medical Technicians (NREMT). NREMT Does not require agency affiliation for any initial certification.

Every state has rules regarding medical direction for utilization of advanced skills as an EMS provider. These rules vary from state to state, and again each person should know the rules for their state and certification rule.