CO Concentrations in Cabin

I purchased a C0 Experts Model 2002 about 1 month ago (it is quite
precise and I am generally pleased with it). When I am climbing out
from take-off, I am experiencing relatively high readings of CO, on the
order of 30 Parts Per Million (PPM). This only lasts about 20 minutes
or so. At cruise, it drops to below 10 PPM (considered normal).

(a) Does anyone else have any hard data about their CO concentration
levels in various phases of flight?

(b) I have read that anything above 10 PPM should be checked by an A&P,
but I have read elsewhere that something like 30PPM for short periods is
not a big deal. Are there any medical-types out there that can weigh in
on this issue?