Core rule: section 12 determines taxable value. Costs incurred by the supplier in providing a taxable service, then recovered from the client, can form part of the service price. Showing them separately on the bill does not alone change their treatment.
Example: a VAT-registered consultant charges NPR 10,000 for a taxable assignment and recovers NPR 2,000 of its own travel costs. Assuming both amounts form the service consideration, the VAT base is NPR 12,000. At 13%, VAT is NPR 1,560 and the total invoice is NPR 13,560.
An amount paid strictly as the client's agent requires a separate review of the contract, whose liability was paid and whose name appears on the original invoice. Do not assume every reimbursement is taxable, or every separately billed recovery is exempt. Keep the supporting invoices.