Hi Vilas
"AOA relative to the chord with flaps down is greater"
I suppose you mean at the same aircraft pitch angle?
I used to think so too, however Boeing, and I think all in depth aerodynamics discussions, take the aoa from a fixed reference line on the aircraft axis, which does not change when one changes the configuration.
The same article in the first link states:
"Angle of attack (AOA) is the angle between the oncoming air or relative wind and a reference line on the airplane or wing. Sometimes, the reference line is a line connecting the leading edge and trailing edge at some average point on the wing. Most commercial jet airplanes use the fuselage centerline or longitudinal axis as the reference line. It makes no difference what the reference line is, as long as it is used consistently"
thanks for the response.