Lets ask Boeing
http://www.boeing.com/commercial/aer...7_article2.pdf
One of the prevention techniques mentioned:
"Consider use of greater flap setting to provide
additional tail clearance on some models."
I do recall seeing something very similar in the 744 FCOM.
misd-Agin: If something like the above is also written in the NG FCOM, I don't see why every operator would then stick to flaps25 departures on every NG takeoff only because Boeing "recommends" it.
Some 744 outfits only use flaps20, while others use both flaps10 and flaps20. In the end the higher flap setting is simply increasing the safety margin on something that is perfectly safe to do in the first place, as long as it is done properly.
I think its pretty clear. The recommendation (if indeed it exists for the NG) should definitely be taken into consideration for takeoffs during gusty considerations. Does this imply the greatest flap setting must be used for every other takeoff? nope.