This might be too anecdotal to matter, but for the last 1.5 years the pattern I notice on both AF and KL is that the returning crew from long haul outstation tends to be on the lower end of the on-board experience scale, than when originating at CDG ape AMS.

Late night outstation departures seem even worse. Though late night from home bases seem to not be as effected. But then again, I had a terrific DEL-AMS recently, which even departed 3hrs late, rather than 4am. So, like I said, maybe it's just something my mind has made up.