Fully concur with aww3583 above (unfortunately "like" does not work again for me ...)
As a long-year "real" diamond (i.e. not credit card gifted), I have very rarely been given anything beyond 2pm.
Personally, I will have no problem paying 50 bucks for guaranteed 4pm check-out, when I really need it - especially given that 11am has been strongly establishing itself as the new normal for standard check-out time.
Otherwise, my experience reflects what HadesNL has noted above, i.e. 50% BAR for 6pm check-out and 100% BAR after 6pm.