Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Bali to Dumaguete City as you normally would.
Dumaguete City (DGT) is the airport you will fly into if you book a flight from Bali to Dumaguete City. It is only a 3.0 km journey from Dumaguete (DGT) to Dumaguete City’s city centre.
This is defined as Denpasar Bali Ngurah Rai Airport (DPS) and Dumaguete City Airport (DGT). Codes like Dumaguete City Airport are often used to just call airports uniquely.