newby question: FIM support and licensing the manager

[Tam Pham]

We are thinking of installing OSSEC+ versus OSSEC Atomic for file integrity monitoring (FIM)

My understanding is that OSSEC+ will give us FIM by itself. Is there an advantage for FIM for installing OSSEC Atomic? We need to file reports around FIM for PCI conformance.

We plan on installing agents on two different systems and have a separate centralized manager to have the systems report to. For OSSEC Atomic the cost for each agent license is $50. Does that mean that the total cost is $150 for the three systems? I am assuming that this would be a yearly recurring cost?

Thanks for your help and pointers.