In my opinion the only thing of importance is to develop a system that works for us as individuals. There are so many variables in how we photograph, stretching from camera and shutter tolerances (especially as they age), material choices, technique with metering and the light meter itself, not to mention how we print and final output requirements.

My Gossen Luna Pro does very well at box speed for me. My in camera meter on the Canon EOS 3 likes a lower than box speed EI for the most part (about 2/3 stop), the Pentax KX requires me to set the film speed at half box speed, etc.

The trick to becoming a good craftsman (craftsperson?) is to know our materials well enough to know what to do in all kinds of situations. Nothing else really matters, regardless of what the box says.