For any given user on facebook, there is a limited amount of promoted posts that facebook will show in their feed at any given time/day so that their feeds don't become overwhelmed with promoted/sponsored content.
So like other ad platforms, i.e. auction based, you are competing for that limited space with other brands and pages that are promoting/sponsoring content. If everyone is competing for the high value fans, i.e. us based fans, it would be easy to get "bid out" by putting in to low of an amount.
But since no one is likely targeting India/Indonesia/Philippines, those are cheap. And if your fans there are all that are available to you because of bid optimization constraints, facebook will most likely end up sending a disproportionate amount of your views to those fans.
Now for some sample math: If you have, let's say 5 friends in Indonesia, let's see how that could play out. Indonesia and Phillipines facebook users generally have more fb friends on avg then the rest of the world. Call it 170. So your potential audience of 'friends of fans' in indonesia is = 850.
Since not many, if any brands, are attempting to target those 850 people, you could saturate them with your promoted/sponsored content. Users in that part of the world also 'like' stuff more frequently and at a higher volume. No let's say that you get 15 likes from those 850 'friends of fans'. That like action will create an organic story in those peoples' friends newsfeeds. So 15 people, with avg of 170 friends each, like that sponsored post and an organic feed story is seen on avg by about 14% of any users friends you could reach 357 more organic impressions.
That cycle can continue on and on.