Originally Posted by
A281
..By the way: I am sure, the flight FRA-SIN-FRA brings the LH a lot of money -> C and F is almost nearly full!
Yes but not with paying passengers.
Upgrade requests from Y->C clear with absolute certainty any day of the week even with standby-only instruments.
The spoiled mercenary staff hired @SIN also upgrade tons of "cute babies" to C upon every occasion. The premium cabin is an absolute mess ex SIN with screamers and novices who try to get used to the C seat all over the place.
C->F upgrades are hard to come by though, I agree.