Where I think the confusion lies is that there are various certification platforms for an acceleration altitude (ICAO, for instance, use between 400' and 1500') for the acceleration platform in the event of an engine failure but this still is not the criteria for flap retraction - its only about speed!
Not quite true, Tom. The JAR's and FAR's also state that the minimum flap retraction height is 400'. My present types (JAR/FAR 25 type) AFM also states this height, although its a rocket and speed is usually way above V2+10 way before this height.
This is another thread on the subject here:
http://www.pprune.org/tech-log/31985...-altitude.html