If you're playing with five or more players and there's a monster surge do you draw twice as many monsters as there are gates?

I think I see the confusion, as when you draw a gate, you place two monsters on it if there are five or more players. But no, you do not double monster surge monsters (or sixteen would appear every surge for an eight player game... yikes!)

I can't find something specifying this exactly, but in the example given on page nine of the main rulebook it gives an example in which seven investigators are playing and only seven monsters are drawn. So, nope!

Oh man, if it worked that way, then each monster surge would be sixteen in an 11 on board max and max outskirts of zero. So that would mean each monster surge, the terror level raises by five. I really hope that isn't the case!

It's not. It spawns a number of monsters equal to either number of people playing or open gates. Whichever is higher.