Our previous corporate discount arrangement had quite a quirk to it (and was nothing to do with agent's commissions). The deal included a higher discount on QF flight than on AA, BA, CX etc. That meant that for a DONE4, the discount varied depending on the mix of airlines (flight number not operator). So I received a bigger discount if I used more QF flights in he mix.

The final price was based on determining the proportion of the total miles flown with each airline and applying the various discounts according to airline code on the flight numbers. So a big incentive to use QF codeshares on USA and European flights, and also to use QF for Kangaroo Route and Trans-Pacific sectors.

In fact, I could reduce the over price paid by adding more QF domestic sectors even if I did not need to fly them. Adding a QF codeshare LAX-ORD-LAX turnaround would add a further 3500 miles of QF component, hence a greater overall discount which could save me $100 or more on the total fare if carefully constructed. It was a strange anomaly that meant adding more sectors reduced the fare!

But alas our corporate procurement boffins stuck a new deal where we travellers pay the full published fare and the corporate coffers get a kickback (rebate) at the end of the month or quarter. So my cost centre gets charged the full fare (plus booking service fee) and the corporate travel dept gets the "discount" benefits . So no more incentive for me to optimise my itinerary for lowest fare so I optimise for other benefits now .