Its not a given that clubs will sell to meet FFP. The reality is clubs might well be prepared to take the hit of the points, it's hardly an astronomical amount of points that clubs are being docked (to date) and especially the bigger clubs might see it more worthwhile to keep and add players to their squads whilst taking the hit of a few points - especially Chelsea. Those relegation threatened, the points will be more precious....
It's done by wages and amortisation though. It's unlikely it will be a one off hit. As everton are seeing.
It will be every year till they sort themselves out.