Seeking clarification on isolation period for travellers

I am seeking clarification regarding the recent announcement on travellers entering the Sultanate, which stated that the quarantine period ranges from two to 14 days, depending on the isolation notice granted by the authorities on arrival.

How about children under 18 travelling with their parents?

Furthermore, those not eligible for shorter period have to complete 15 days of quarantine despite having tested negative for COVID-19 on the 12th day. Given the clean bill of health, would it not mean that they have confirmation that they are not infected?

I hope the authorities could address the confusion of travellers in relation to the current measure, especially the markers used to determine the duration of the quarantine period.