The Commission's ruling, found a worker's typical shift should be used to calculate the total number of hours meaning a shift-worker who does usually a 12 hour shift should receive 120 hours of paid leave per year.
Using the arithmetic quoted, to arrive at 15 WORKING DAYS (your bolding) that would necessitate Qantas deducting 5 hours per day for each day sick? (76/5)
If that is how it was applied before the FWA ruling it would be appreciated it as suggested above, the relevant excerpts be posted showing the calculation.