Its Motabilities company and they are good at changing the rules to keep the company profitable.
Factor in the change from ICE to BEV, and its understandable they will keep lease extensions at 6 months for ICE cars as they need to auction them off ASAP. Motability are after all pushing EV,S as much as they can.
It would be interesting if a BEV are given the same 6 month max extension??
But yup, if Motability want to move people away from ICE, that is certainly one way to do it. Shorter and shorter lease extensions.