I would like to see the measurement on the 38. Please lay the coat out on a flat surface, chest up. Pull the fabric tight and then let it relax. Take the measuremt across the chest from just under one armpit to just under the opposite armpit. It should measure about 20" plus a fraction, and will probably be about 20.25" plus or minus .25". Sometimes there will be a jacket with a non standard chest size, but most (95%) fall in this range.
Alrighty, so my chest measured 42" at the widest point, moving the measurement just down slightly brings the chest measurement down accordingly. My chest measures 38" at my *ahem* nipples. I can wear a sweater under the coat no problem, but then again, I am used to wearing tighter, fitted clothing.
The jacket measures just under 21" across. I would have to say it is about 20.75".