I would imagine that these pre-retirement days were conceded on a quid pro quo basis & employees through their representatives made cost saving concessions.
I would readily concede that this is a supposition on my part as no background info is to hand , certainly the Indo has not published the reasons for the granting of the pre - retirement days.
Man, imagine what they must have 'conceded' to only end up with an extra 44 days each for the last 2 years!!!! now that would make good newspaper copy