i have tested papers over the years.
at one point i had a chart of maybe 10-15 papers
that i ran iso tests on, from azo to oriental ... rc and fb, graded and vc
i too have never been able to get my paper to agree that it is
iso 25 ... maybe PE is using a bluer light than we were using ..
i have only used daylight and strobes .. and my numbers
are similar to yours ..
PE what lighting are you using, something that is more blue-rich?