45 seats blocked is correct. However nowhere near 19% of the ASK
Well actually it is. Understand the revenue premium to which you allude, the revenue mix is not 'counted' with an ASK, it is simply the seat count times the stage length.
From the outside yield on a route is a very inexact science as there is simply no way to know the prices paid, the upgrades and redemption against other centres in the airline itself (like Frequent Flyer)
The point of the post is that if there are environmental conditions leading to a targeted weight reduction then the 'range-payload' mix attempted is sub-optimal. This suggests an aircraft way beyond
optimum route selection criteria.
No doubt in 'milder weather' it can arrive carrying a full ASK load, but with headwinds or a range of weather variables impacting an arrival such a situation reduces the available options the aircraft is beyond the designed optimum. Airline network planners refer to the sweet spot. This is not it.
Points for trying, but square pegs and round holes. Qantas lacked the appropriate fleet.
These environmental variables are the things that aircraft selection and route optimisation is intended to alleviate. That such circumstances can see an aircraft, with substantial ASK reduction, perhaps also with fuel on conclusion of landing roll approaching statutory minimum is from an aircraft evaluation and suitability perspective, an aircraft operating well beyond optimum.