It's not based on destination time. On NA flights, it's based on departure time. On International flight, it's usually based on origin time as well because of the time zone differences and one would expect that most passengers' body clock is set on the International origin. On the Asia-YYZ that you mentioned - it's not that it makes no sense, we've done non-breakfast before and many many feedback told us one would prefer breakfast because by the time one lands in YYZ, it's middle of the night at origin and one doesn't want a heavy meal right after getting up.