150 agents and operators, not 150 total men. The Normandy cell includes an entire crew plus however many people were involved in the construction phase and possibly all of the personnel and resources of the Lazarus project if you want to include them with the Normandy cell(Shepard is the captain after all, so it makes sense) and yet Miranda and Jacob are the only two people involved who hold the rank of operative. If that's proportional it would explain a lot.