Iphone app free ... ipad NOT ? ...but already subscriber..!? Pro or not? What is going on here !?!?

Welcome to the forum!

If you are subscribed to Pro on Apple TV, you can simply download the free ‘Infuse 6’ app on your other devices, and your Pro subscription will be automatically recognized.

Alternatively, Pro is available as a one-time purchase via the paid ‘Infuse Pro 6’ app. This contains the same features as your Pro subscription, but will not include updates to future major releases (v7, v8, etc…).

Full details on the differences can be found here.