I couldn't find the exact scenario the OP alluded to (and without the details, it is hard to know for sure). But I searched for an F award, LAX-HNL in September and found two days with different "low" pricing. The 16th the lowest was 50,000 O flight. The 17th had a 40,000 R flight.
IIRC, the only flight to HNL that had different pricing was the non-stop from ATL, or were there others? An award chart would really be nice for situations like this...

What's an award chart????