I booked IAH-EWR-IST July 5, WAW-MUC-IAD-IAH July 15, intended to book Y, but I got the "upgrade to BF for $X" message, and the total fare in BF (P class) for the whole itinerary (including the LH leg WAW-MUC) was $3,400 (versus $1,800 in Y), so I snagged it. This seems like typical Europe summer sale pricing.