MarkOne's point seemed absolutely valid? Can you access the Xbox movie service with a £159 XBox? Taking your own figures, it's a £200 XBox you need apparently (or £239 if you buy separately). Retail prices, however, would seem to make it a £279 console needed (including all necessary options and subscriptions).
Whichever way you look at it, £159 comes across as being way short of the mark, and therefore misleading imho.