The .5 ounce simcoe at 30 minutes is sort of a waste in my opinion. You won't get much bittering from it, and you won't get much flavor either with a 30 minute addition.
If you need more bitterness (IBUs), increase the 60 minute addition. I'd move the simcoe to 20 minutes or later in the boil, to get flavor from it.
I'd change it up just a tad, like this:
Columbus - .5 oz 60 min (or whatever you need to keep your IBUs where you want- maybe .75 ounce, I didn't look at the numbers)
Simcoe - .5 oz 15 min
Amarillo - .5 oz 10 min
Simcoe - .5 oz 5 min
Amarillo - .5 oz 5 min
Amarillo - 1 oz 0 min