So I got my good old Zone VI modified Soligor spot meter out to check how many stops I lose with my recently acquired Cokin filters and was surprised to find they're not very similar to my old gel filters.

The 003 (red) metered between 3.5 and 4 stops less.
Orange about 2, Yellow about 1, Green about 2.

Is this consistent with other people's experience.

Not that "Sunny 4" on my Bronica 80mm 3.8 is a bad thing....