When flying from Malaysia to Latvia, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.
These are just IATA (International Air Transport Association) codes. They are used in aviation to identify and differentiate airports. That’s why a Kuala Lumpur Intl Airport to Riga Intl Airport flight would often be abbreviated as a KUL to RIX flight. Ready for more IATA code knowledge? These are related airports for your current travel destination: Kota Kinabalu Airport (BKI), Penang Intl Airport (PEN), Kuching Airport (KCH), Johor Bahru Sultan Ismail Intl Airport (JHB), Langkawi Airport (LGK).