Looking at RTT it appears some are listed as standard class only [i.e. 13:53 Leeds - Huddersfield today], but some are showing as "First & Standard" [i.e. 14:53 Leeds - Huddersfield]. So I guess the odd-hour departure is meant to be the 170 with the even-hour departures as the 185?
They're wrong then, as the 1453 (which I'm sat on as I type) is a 170 (478 for those interested in such). Yesterday's 1929 arrival at Huddersfield was a 185, but we great unwashed were allowed to sit in 1st.
EDIT: the 1453 ex-Huddersfield is a 170, not the ex-Leeds.
Either way, I can't imagine that having first on only half the services is workable. It's only a matter of time before the diagrams have to be swapped for whatever reason and anyone with a first advance will be due some money back.
Of note, the change seems to require more use of P5 at Huddersfield for the Wakefield Kirkgate service, meaning the May upgrade of that service to a 3-car 144 will have to end (P5 is max 40m). A dogbox is on that duty today.