Does "available to members on a complimentary basis at booking" mean just that, or is it similar to the new Delta Comfort+ debacle (upgrade available, except when it's not, and there needs to be "Comfort+ upgrade" fare class availability which you can't actually see until after booking)?

I'm assuming this will be something along the lines of MVPG + 75K free at booking, MVP for a certain set of fare classes (K+? H+?), and general members on YSB fares?