Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Kuching to Amman as you normally would.
Related info for your journey
Useful info, stats and facts about Kuching to Amman flights.
These are just IATA (International Air Transport Association) codes. They are used in aviation to identify and differentiate airports. That’s why a Kuching Airport to Amman Queen Alia Intl Airport flight would often be abbreviated as a KCH to AMM flight.