I always thought that the Get More Coverage option meant that people that have NOT subscribed to my page will get my post, as an ADVERTISEMENT, based on some algorithm where at least they target people with that interest (as my page).
It possibly might have meant that in the past. But I do know that the relatively new features facebook have added prevent people with facebook pages from getting their content out to all people following them unless they pay extra. I think they may be working on adding exceptions to this (possibly for non profit organisations, etc).
Note also there is a separate advertising program that marketers can use to target people with interests, etc (you can target by interest, by people who have liked a particular page [yours or someone else's], etc. I'm not talking about that program at all. Rather, I am talking about your own content being send to people already following you (having liked your page).
Interesting times to see if they are just going to upset their userbase.