Claire,
What a great ad, really nice to see a early ad for Chanel. I think the copywriter or typesetter made an error in capitalizing the "Y" in yoke. It should read "Long Coat, yoke and sleeve lined". So the shorter jacket has a full lining, and the long coat has only the yoke and sleeve being lined. So there is no "long coat yoke".
The photo is rather grainy, so I cannot see the details on the hats, but the dress, shoes and hats all are mid to late 192os. I am leaning to 1927-1928 ish.
My guess is the jacket is less $ simply because it is shorter in length.
Thanks for sharing this great photo.