Someone else who knows the stats could probably confirm this but I'm guessing you would make x amount of dollars if you don't double, and if you do double x+a little bit more.
Basic strategy says to stand with 12-16 against a 3-6 so its not like you would have hit your hand again anyway.
If you get a ace, 10, or 9 then you got a pretty good hand and a good chance of winning but even if you get stuck with a 2, 3, or 4 remember that when the dealer shows 3-6 you're hoping for him to bust. Its probably not as safe as doubling with a ten or eleven but thats why you don't double on a 9 as often.
