Number of authorizations

That depends on the reader. If the reader prompts you to enter a username and password when deauthorizing, then yes it recovers that use. If it doesn't when deauthorizing then that use it lost. If you sign out of the reader and sign back in on the same computer WITHOUT reinstalling the application it won't use another use against your allotment. You can authorize up to 6 mobiles devices AND 6 desktop computers at a time. Once you bump into the limit you'll have to contact Adobe/ADE support.