FAQ item: release date for Premium is +1 day or more
It's mentioned at the end of the Arifureta v9 thread that the typical delay for Premium editions is not documented - https://forums.j-novel.club/topic/2136/arifureta-v9-disscussion/126
It's a valid point. People eventually learn from random posts or by having to wait that the release date does not apply to the Premium editions, but it's probably worth adding an item about that into the FAQ to make it official.
I agree that as questions go it is quite frequently asked. Seems like if JNC wish to continue with this practice they should ensure that potential customers know they'll have to wait a day or so for premium.