Hi Mike, you can use PIServer.GetPointCount Method to get the number of points created. However, I don't believe there is a way to get the number of points licensed for (or available points) via AF SDK.
The way we do it internally to get number of points licensed is to make RPC calls with PI SDK to get it but we do not expose that interface documentation to the public. Perhaps this can be an enhancement request for AF SDK.
Although you can't use PI AF SDK to obtain the total amount of PI Points available, you can use either piartool -lic def or pilicmgr -lic def and process its string response programmatically using C# or PowerShell for instance.
One of this fields should be: ------ pibasess.maxpointcount ------
This should have the information you are looking for!
Hope it helps!