bmused
I think the AC savings would partially come from replacing 343s per se due to the increase in load capacity but also in collapsing the number of types and variations in the long haul fleet with consequent savings in training and spares.
AC operates 343/345/333 (all 777 replacement under the aborted order) and 762/763 (787 replacement) and within some of those types are mark variants arising from second hand acquisitions (343) and engine variations remaining from the AC/CP merger (762/3).