Not just a company requirement. From the FCOM word for word....

cp..... we know it's in the FCOM but feedback on the line from loads of different operators say leaving the flaps extended is more hassle than its worth (me included) . I'll deal with the bleed warning but I can't deal with a fueller refusing to fuel with flaps extended, then your into electrical switching retracting flaps and extending etc. I've flown into loads of places in the late 30s and never have had the warning like wise the FCOM says less than 115 pax on a 320 or 140 on a 321 pack flow to low/econ.....another ecam warning waiting to happen.....anytime I have used econ the pack compressor outlet temps have gone v high and have had spurious hot air ecam warnings. Like the flaps I leave the pack flow norm and attempt the crossword without interuption.