A lot of this is all semantics. All shops worth their salt use pressure filling systems, either bulk or batch, to fill transmissions. This could be something as simple as a hand pumped tank (batch) or pull down over head lines (bulk) commonly seen at larger facilities:
Both deliver the fluids under slight pressure, but just enough to get it into the transmissions. They are not flushing systems, but delivery systems. A pressure flushing system attaches to the external fluid lines on cars equipped with such lines, and push clean fluid through the transmission, pushing out the old fluid:
Pressure flushing systems operate at much higher pressure than the filling systems, but lower than the actual line pressures developed inside the trans when the car is running.