They did that on all the larger (250+ sized) Deluxe and Supermarin skimmers. The 50 watt is sufficient and I wouldn't run the 50 watt let alone 60 watt at full power on that skimmer anyway. A string of between 38 and 45 watts on the Deluxe 250 is really where you would want to be unless the sump level is really low. It was done to keep the bill of materials more common between those skimmers.