I don't have one and have never seen it, but from what you say, assuming that the chainring is centered to the outer cog, the angle of the chain when just 2 cogs over isn't that big of a difference if you compare it with something like 8, 9, 10, 11 speed cassettes. If you're worried about the chainline, you could always measure the chainline at the cassette and at the chainring, then adjust the chainring position, either with bolt spacers, or using a different length BB or BB spacers.