Length varies quite a bit for me. Most plaids / flannels I have are about 29 or 30, oxfords and ginghams are 31-32 or so. I think one source of the differences in sizing is that Gitman sources so many difference Japanese fabrics that have different shrinkages. Given how shirts are made, the majority of shrinkage would be in sleeves and length
I understand shrinkage, and I've experienced sizing differences among fabrics and seasons with GV, but this is extreme. It's such a variation that I'd say it's a mistake on Gitman's part.