Guess the way I'd see it is that any given club has a relative degree of urgency on spending efficiency in relation to PSR headroom.
If efficient spending relative to PSR is a lot less urgent for any given club, then it could take a PSR hit on any given deal, and simply offer to keep track of a kind of Monopoly money to cover it, a shadow credit to be redeemed as a favour on some later, more urgent transfer.
