I'm thinking it is poor wording based on deficient technical knowledge. I am thinking the high gain antenna raised the Effective Radiated Power, not the actual radiated power.
gain antennas concentrate power in one direction, versus omni antennas. a 25 meter dish has a 3 db down beamwidth of .1 degree. Imagine all the sunlight hitting the earth concentrated in a 6 mile diameter circle, but outbound.