Originally Posted by
WilcoRoger
Somewhat surprisingly AY/AY is cheaper than JU/AY flight numbers. This gives a great many options via FCO/VIE/WAW/etc. ^
It is not that surprising. AY/AY-JU/JU is an interline ticket, which can most certainly not book into the cheapest fare buckets. Before the last ticket type rebranding, that sort of ticket would book into Value at minimum.
AY/AY-AY/JU is an normal AY ticket, so while you obviously won't find sales on that route, you might have more/cheaper choices of fares. Of course, the issuer will be 105 either way.