This will likely depend on the specific regulations in force in Bangkok at the time, and possibly the model of taximeter installed1.
However, for the one model of taximeter I could find an operations guide for it was clear that the operator had an option to Pause the meter (from which he could press Pause again to resume the trip), but once Pay was selected then the only available option subsequently was Reset.
If the taxi driver believed that the trip was complete he’d probably go to Pay, and quite possibly he would have no option but to start a new trip. If he understood that the trip was to continue he’d have just left the meter running.
1 Taximeters have software tailored to the specific market they’re intended for. If a specific sequence of operations isn’t covered by the regulations then different models of taximeter may operate differently.
Credit:stackoverflow.com‘