I was always second guessing my meters. I had a hand held from Zeiss (Euro), a Gossen (Euro), a Pentax Spotmeter (Jap.) and several Nikons also Japanese. The Nikons were very close to the Pentax but the Zeiss and Gossen were not. I always thought the Pentax and Nikons were out and reduced the IE accordingly. The Zeiss and Gossen always gave me dead on chromes, once the usual high velocity fudge factor is adjusted for.
Darn I hate testing, but now I think I might have to. Actually I will be out with some very anal LF types (and I say that in a nice way) this weekend so will compare my meter to theirs and see what exposures we would come up with given an identical subject and effect wanted.
Will it ever end!!