Our company policy was - if QF is in cooee of DJ, go QF, otherwise yagotta go DJ. Our Chairman tested the policy with a late (cheap) DJ fare BNE-MEL.
After a 2 hour op problem with the DJ flight, which got him home at around 2am, the new policy was:
"No more Virgins".
We also looked at the economics of using K only, or low fares. The board decided K was the go. It just doesn't work for most people in business who have a family at home, and the business doesn't want them spending too much (wasted) time in the QC because they bought a cheap fare to save a few dollars.