As I understand it, EZY sell a fixed number of tickets at each price-point. If your group booking straddles price brackets then ALL seats in the reservation will be charged at that higher price. This isn't necessarily gouging, merely the constraints of the reservation system.
Try reducing the number in the group, one person at a time, until the lower fare appears. Then complete the reservation for the rest of the group. Given that there's no pre-assigned seating, this wouldn't necessarily split you up.
Hope this helps.
