EASA/CAA requirements for number of cabin crew are 1 for every 50 seats or fraction thereof. 214 SEATS requires 5 cabin crew even if there are only 90 passengers... 200 seats requires 4 cabin crew, Any larger crew compliment is based on service and company needs. But when getting an AOC the company goes through an egress evacuation with the minimum crew they will use. They can always add to the crew once they have passed the CAA egress. But they can never operate with fewer than what the CAA approves.