What @Bahbus said.
Here’s an example I have been contemplating that might help.
I am considering building an event app for a local festival for event goers to get detailed information. There would be tens of thousands of users and I don’t really care who those users are so I don’t need them to login. They’ll just be reading event information. A Publisher Pro app at $50/month would be perfect. AND I’ll likely only need it for a month or two before the event.
HOWEVER, I may want the vendors to be able to update their specific event information. I’ll need them to login so I know who they are, only show them THEIR info and allow them to make updates for the event goers to see. For this I will need a SECOND app that’s on the Pro plan @ $10/vendor/month. I’ll probably need this app for many months as vendor enter/update info in prep for the event.
Two apps on different pricing plans updating/using the same data source is acceptable.