If you go to PJCentral and use their calculator, they automatically adjust for the initial bulb dropoff and for content. Bill had asked them about this a few years ago and this was their reply:
So if you use their calculator, the numbers should be pretty close to what you should expect. That's where I got the 60fL number from. :T In a typical Home theater environment, the minimum fL should be around 12. I ran my Mitsubishi HC3000U at around 10fL at times in ambient light. It still performed fine to my eyes. And yes, pre-calibration and post calibration fL readings will be different - they'll be lower.Projector Central said:Our calculator pre-ages the lamp by 25% before it does its calculations. We do this so that people do not setup their projectors at maximum lamp performance, but rather halfway through the lamp life. This ensures a quality viewing experience throughout the life of the lamp. Therefore, you can expect our fL to be 25% lower than you would calculate with a new lamp.
We also assume a projector has an ANSI lumen rating calibrated for presentations (9000+K) unless the manufacturer states that it is calibrated at a different color temperature, such as 6500K. This means that if you take a projector that is calibrated for presentations and select Video/Movies or Games as your Primary Use, we will automatically reduce the lumen output of the projector based on the new color temperature that is required for video.