Originally Posted by nufnuf77

yes, but in case of irrops you are stuck with a family in tow.
what's causing the price difference is actually your stopover in london on the way back. May I advise you look at buying IAD-LHR-FCO // LHR-IAD. And a separate ticket for VCE-LHR. It prices up lower than the direct return when I look at random dates.