people making connections to that flight vs you originating on that flight out of Denver.

chevk in is based on starting point departure. If I fly on the same flight as you and I fly from say Dulles to denver and we both booked the same ticket under the same status and not ECBI purchase I get an earlier boarding time than you do because my board time is 4+ hrs before yours.

WN usually has am flights to denver from central and eastern cities feeding thst flight to hawaii if it’s a later day flight. If the flight leaves around 8 am you may have only a limited number of feeder flights from say KC, Omaha, albuquerque while if it’s after 2 pm you have flights from all the east coast cities.