Maybe I'm wrong then, but any shirt I've purchased off the rack - i.e. Brooks Brothers, Nordstrom, the Bay's house brand (in Canada) has always been 32 or 33 for a size 15.
Perhaps I can ask then, would the 34 length look baggy on my short arms?
Two pairs up for sale, the Slim Guy pair is Natural Indigo Selvedge with a size 30 waist. The Regular guy pair is Lightweight Indigo selvedge, also a size 30 waist. Asking $40 each, buyer pays shipping fees.