Core rule: section 6 generally uses the earliest relevant invoicing, delivery or receipt-of-consideration event to determine the time of supply. Calling a customer payment an advance does not automatically defer VAT until the final invoice.
Example: a VAT-registered supplier receives NPR 10,000 as taxable consideration excluding VAT before delivery. Assuming the ordinary 13% rule, VAT is NPR 1,300. If the agreed NPR 10,000 is VAT-inclusive instead, the VAT component is NPR 10,000 x 13/113, approximately NPR 1,150.44.
Document the VAT-inclusive or exclusive basis and issue the required invoice. At final settlement, reconcile the advance and VAT already recognised so the same consideration is not taxed twice.
A genuine refundable security deposit needs separate analysis. Its label alone cannot decide whether it is consideration for a supply.