To be clear (and terminology is important), there are no Qantas Business "Classic" Awards available on the dates/flights you are searching being shown.
What is being presented in this case are "points plus pay" awards which basically purchase a revenue fare valuing Qantas points at much less than a cent each.
Actually Qantas add the points together for each individual "Trip" as defined in the QFF terms and condition.
A "Trip" may involve between 1 and 16 sectors.
