easyflyer83 was absolutely correct. Procedure is that if you are operating with minimum crew (A320 that is 4) and, for whatever reason, you have to depart a non-crew base station with 'reduced crew' then the passenger figure for the A320 and their A319 has to be reduced to 150.
RE: EZY's decision years ago to configure their A319's with 156 seats actually goes back to EZY and Airbus wrongly believing that they could get an A319 with that config certified to be operated by 3 cabin crew if the second overwing exit was adopted. Since then, there was a trial where 6 seats were physically blocked off but long term this was decided against by the airline.
Finally, there seems to be a couple of comments and misconception regarding cabin crew pay. Certainly when I was there, not that long ago, cabin crew pay at easyJet was actually pretty good. A few years ago a full time UK based junior would earn around 23K with a senior between 25K and 28K. Commission would only account for about 3K with some 'Northern' bases earning up to 5K. It's hardly the poorly paid job that some seem to think, certainly in the context that 26K is the average UK salary. The problem these days is that contracts can often be fixed term to start with. Even so, for money the charters and some LCC's are much better paid than the legacies on todays contracts.