Since we come to Easyjet and their crew what is the point of having 156 seats on an A320 thus for just 6 more passengers a fourth crew member is required which is good for the crew numbers. The question is why the airline did not op for 150 pax and 3 crew?
It is correct, it is one cabin crew per 50 fitted seats, not one cabin crew per 50 bums on seats.
Alas the aircraft designers, bearing in mind that so many different operators have different seating configs, do not make airliners in multiples of 50 seats to optimize cabin crew utilisation.
Should any 156 seat operator choose to reduce staff costs then they have the option to remove 6 seats, on the other hand the beancounters have probably had their abaci out and reckoned that those 6 seats earn more revenue than the p1ss poor salary that additional cabin crew member may be paid.