BOAC : At 27' RA normally if A/T is engaged, single or dual channel. FLARE is a separate function and nothing to do with the A/Throttles.
That's not true. In Dual Channel, Flare Retard occurs at 24' RA AFTER DFCS goes to FLARE mode. The DFCS sends a flare discrete to the autothrottle computer.
It's interesting to note that it appears that single channel A/P does not follow the same logic.