Appointments + plugin question

Hello,

I installed appointments+ plugin on my multisite. I had to enable it for the whole network for it to work and customized.

I am wondering whether this plugin can be offered as a premium plugin using Pro Sites?

I deactivated to see if I saw it under premium pro site plugin but it was not there.

So, I'm I correct to assume that it cannot be offered as premium pro site plugin?

Thanks for the info.
Janet