maxalt,
DUB-LHR is not the only route EI flies. If it was, your maths would be spot on. What I said was, an A320/321 CAN have 15-20 biz rows, but the other routes never see more than 8 or 9. On average, it surely works out at no better than 11-12??
Your figures assume every flight is a peak time biz heavy flight, I'm merely saying it's a bit of a stretch.