When comparing duration numbers, be careful that you're comparing apples to apples. Make sure both numbers are total duration, or duration at .050 lift.
Most cam grinders now give duration at .050 lift. This is an easier number to deal with as it's easier to figure out, when degreeing in the cam, where the .050 lift points are than where the valve starts to open, i.e. .001 lift. The valve doesn't really start to flow much air until it's .050 off the seat anyway.
