Ah, yes, for foodstuff one does often use S, M and L as localized sizing labels, Burger King does the same, I think. However, in the context of localizing XS as being extra large, and XL being extra small, that's still wrong. Anecdotally, wherever XS to XL sizing labels are used it's always been direct counterparts. XS bring extra small, and XL being extra large.
