I doubt it is an "honest mistake" by the Crew Planners, and would be more inclined to believe it has been (repeatedly) another cynical attempt to recreate a facet of the "Ryanair model", that rather ironically, Ryanair are themselves slowly moving away from.
If it was just that, a simple miscalculation, the company would have in all likelihood bit the bullet, picked up the tab, and kept people employed over Winter . . . . there was no miscalculation here, believe me.
