Interesting. We tried to check in about 9 hours before our flight at the F desk but were told to come back 4 hours before our flight. To be fair the agent spent about 10 mins trying to get us checked in and got his manager to try too. If it makes any difference we were on a J ticket and were just at the F desk as there was a big queue for J so the F desks were helping out.
We ended up spending about $60 to leave our bags at the left luggage desk at the other end of arrivals.