Incubation- Single and multi stage systems

Dr. Wineland discusses an important advantage of the single stage incubation process - the economic advantage! We are receiving many customer reports confirming increased viability, increased weigh gains, and (maybe subsequently) improved feed efficiency. An area which we feel has been erroneously commented is that single stage incubation is a more expensive process - mostly due to an increased electric charge. Again we are learning that there is in fact less electric usage with the single stage incubation process. In well insulated cabinets with no air leaks,by closing the cabinet for the first days of incubation, there is little call for additional heat once the cabinet has reached temperature. Single stage incubation is a real aid in reducing production costs.

good comparison. but its astonishing why still some are companies adopting multistage?