What a creative way to have a reason to 1) give money and goods to the people, 2) check to make sure the emperor is maintaining his health (or not), and 3) give the people a party!
The Astrologers determine the date and time of the weighing, and after the Elders pray for the prince, they weigh him on a great scale. The hope is that his weight would increase year after year. The amount the prince weighs will determine the amount of goods given to the people. The courtiers would distribute newly coined gold and silver, silk, perfume, copper, mercury, ghee, rice-milk, medicine, grains, salt, and livestock. Emperors give all twelve types of goods on their solar birthdays, but a prince will only be giving a certain number of goods based on his age.