Dear Bigdog,
Sorry, I didn't mean to offend you. All I meant was that personal metering variations are so great that EIs need to be treated with great caution. Someone who meters the way you do (which is the best way for negatives) can rate the film faster than someone wo uses an incident-light or in-camera averaging meter.
I'd also totally agree that modest overexposure -- 1/3 stop to 1 stop -- is ALWAYS wise.
As for 'push' and 'pull' I'd say that many of the people who use these terms don't actually understand what they mean -- again, I don't mean you, but what follows is for lurkers.
ISO film speeds are based on sensitometric (not in-camera) testing with the film developed to a constant contrast, roughly a gamma of 0.62. They are (or should be) based on a stated developer.
Develop to a higher gamma and you are pushing; overdevelopment lifts the speed point. Develop to a lower gamma and you are pulling: underdeverlopment depresses the speed point.
Use a different developer that gives a different film speed at the same gamma and you are neither pushing nor pulling: you are changing speed through developer choice. Something like Microphen can give a true 2/3 stop speed increase, maybe a little more, lifting an ISO 400 film to ISO 650 or better. A fine-grain developer can wipe off almost any amount of speed, but 2/3 stop to 1 stop would be common, dropping an ISO 400 film to ISO 250 or below.
Then there are metering variations (as already discussed); with anything except spot metering of the shadows, there are the 'fudges' needed to be sure of adequate shadow detail on a sunny day. And equipment variations: the shutter on my Pentax SV runs a stop slow so I can rate HP5 in DDX at 1250 and still get the same exposure at the same dev time as at 650 in my MP.
And of course some people just prefer the results they get at different speeds. They may or may not be pushing or pulling -- but a lot of people who rate (say) Tri-X and 200 and develop normally, to the standard gamma, still refer to it as 'pulling' the film.
Cheers,
Roger (
www.rogerandfrances.com, where in the Photo School this is a whole free module on ISO speeds)