Have we not all heard of the drag curve, flying this slow will burn more fuel.
VB's CI's are seriously flawed. QF uses a lot higher CI's (someone confirm).
Our CI's have not changed by more than 5 units in the last 3 years. What has Sing Jet done in those 3 years.
Mate at PB says they are experimenting with LRC or higher CI's and burning less and taking up to 10 minutes off 4 hour legs.