I think they've always been legal if the legislation in the country allows for longer fixed term contracts... What FIFA regulates is the maximum duration for which a contract is protected by FIFA. I think these Chelsea contracts aren't meant to go to their term, all players will either get sold before 5 or sign new contracts in the meantime. They are just doing it for accounting purposes, to accommodate FPF. If you buy players for 300 M and do the amortization over 5 years, your yearly cost is 60M. If instead you spread the amortization over 7 years, then you can register an amortization of around 42M/year... Meaning you've lowered your costs by 18 M/year. This can save you from breaching FPF regulations.