When you see averages listed for each college, is that the composite score? Or is it just the eng/math?
Prepared to NOT be helped as I really have no idea. 
It’s clear to me that they only consider English/math score for admissions decision purposes, but it’s not at all clear to me if the published averages you see here and there are only English/math scores or regular composite scores that include the other sections.
I’d guess that they’d be consistent, but I’m also thinking that it’s possible that the averages you see are developed for purposes of providing data to college ranking services which may require composite scores and thus override the English/math filter.
CSUs only consider the ACT composite score, which is converted to equivalent SAT scores (CR+M, out of 1600) for admission purposes.
The ACT scores for entering freshmen by Cal Poly college shown on page 2 of the “Fall 2015 Census Admissions Info BRIEF” are composites.
The census you link reports the composite scores of new enrolled students, along with the scores for READING and math. I wonder why it’s not for English and math.
The table very clearly states SAT Reading; the only ACT score shown is the Composite.
Oops. While somewhat snotty about it, you’re very clearly correct. 