When flying from Bali to Bamako, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.
Bamako (BKO), located 12.5 km from the city centre, is the airport you fly into when you book flights from Bali to Bamako.
These are just IATA (International Air Transport Association) codes. They are used in aviation to identify and differentiate airports. That’s why a Denpasar Bali Ngurah Rai Airport to Bamako Airport flight would often be abbreviated as a DPS to BKO flight.