I recall reading somewhere else that X-Sync rings mounted to a standard 110 BCD crank will move the chainline 2mm outboard vs. a the standard 2x setup (midway between the two rings). I got the impression from the article that this is the way SRAM designed it and they thought it was more/less optimal for 1x. Why you wouldn't want the 1x ring to be centered between the old 2x rings which presumably would match with the center of the rear cluster, I don't know.

- Mark