What this shows is that two of these boards running 200W each (400W total) are a direct replacement for a 600W HID. Not only will this save 1/3 on power costs, but it will keep the room cooler in summer and may negate the use of aircon (at a significant additional cost saving).
To put things into perspective, there are 8 stations in this room and running LEDs would be the equivalent of removing 2x 600HPS lamps (1200W) for the same yield. Also, no new bulb costs every 2-3 grows, and no 10% light drop-off after the first grow (as HID lamps do, and continue to deteriorate for the life of the bulb).
My mate needs no more convincing that LEDs are a viable replacement for HIDs, so it looks like we might be buying a few more of these after the next trial.