I don't know anything about Filipino demographics but a LOT of Indians that come to the US who aren't highly educated, end up starting small businesses in retail, etc, because that doesn't require a high degree, just raw hard work and perseverance. And those translate to really good incomes.
Might be the same thing with Filipinos?
It's probably because a large share of them work on ships(both, trade and passenger ships [1]) where unqualified workers often can earn slightly more. (I did not find a source on comparable wages, probably someone else has data on that...)