If I purchase the Paramedic level, do I have access to the previous levels. It would be nice to be able to refresh on AEMT knowledge as well.

When you have access to the Paramedic level, you have access to all the levels at once. They aren't split up but available in the Paramedic level since the Paramedic level covers all levels of EMS. If you are wanting separate access for the AEMT level, we would need to set up a different account for the AEMT level. There isn't a way to access two different levels of testing on the same account at the same time.