The quotations are from manuals of AOA instruments operating by measuring pressure differences when AOA changes with a probe located on the lower surface of the wing. Similar to a Pitot-tube (two holes: one is paralell, other is 45 degrees down).
The picture is a snapshot of Aspen's Glass Cockpit. This system calucates the AOA from the ADC, AHRS and GPS informations, and strictly software based, no wiring, no probe.
Each of those instruments actually measure a higher AOA with flaps compared to CLEAN.