I wasnt looking at it from that perspective, I just plugged in your grain bill into beertools pro and with 7 gallons of 1.056 wort, after a 90 minute boil and an evaporation loss of 1.27 gallons, a final volume of 5.5 gallons of 1.072 wort equals 87% effeciency.
if this isnt what you were...