If you go back and read my past posts, I have always held that it's unclear whether check-in time really affects battlefield priority on NW. And I don't know that anybody has ever given a truly authoritative answer as to whether check-in time ever mattered.

The FT NW Forum consensus has long been that the only two factors in battlefield priority for non-Y fares have been (1) status and (2) check-in time. I've propagated that info at length. But I'm really not sure where that theory came from.

We know that CO used to prioritize based exclusively on check-in time, and that they explicitly changed it to prioritize based on fare class. But AFAIK nothing official has ever been said by NW on the matter.

That said, I have long suspected (and shared my opinon with this board) that completing OLCI at the 24hr mark is NOT a good idea if there is still F availability that could be converted to R. Everything I've seen suggests that once you complete OLCI, you remove yourself from eligibility for EUA, so if any F availability gets converted to R after you complete OLCI but before the GA processes battlefield upgrades, somebody else could then snag the upgrade if (1) EUA runs, or (2) they say "yes" they want their elite upgrade at OLCI or the kiosk.

Note that this last paragraph does NOT apply to CO, where I am 99% certain you remain eligible for EUA and kiosk upgrades even after completing OLCI.