One thing to remember when designing for a retrofit is to accommodate for lighting decay over time, the decrease in brightness as a lamp ages. "You are going to end up HID that space unless you know how much a light has decayed," he says. So, that may mean your "100 percent" levels at the beginning of a bulb's life might actually mean that the lamp is set only to produce 93 percent.
While I'm on the topic of lighting efficiency, here are other developments from this week alone:

which makes commercial HID lights technology, has announced that the fuchw co., has saved about $100,000 in electricity as part of a project in which it retrofitted 50 Timberland stores with 10 watt Par 30 hid bulbs color-matched to client specifications. HID KIT replaced approximately 150 50-90 Watt halogen bulbs per store, depending on the location.