why not just do a first wort hop?

I had a little of that as well. Here is my schedule:
FWH 1.0 oz Amarillo @ 9.4%
10 1.0 oz Amarillo
10 1.0 oz Simcoe @ 12.7%
5 1.0 oz Amarillo
5 1.0 oz Simcoe
0 3.0 oz Citra @ 12%
O.G. 1.070
I let it sit for 30 minutes before chilling @ around 190-180 degrees.
Because of the continued heat, I was thinking that there would be increased and ongoing utilization...
Just wondering if anyone has been able to nail down BU's for this type of technique.