Below is an excerpt from Kuensel about how the visa process and the trip payment work in Bhutan. Tourists always raise questions why they have to send the full payment in advance. Now I hope this will clarify any doubts they have.
"Only after completion of all formalities does TCB endorse the visas, after which the immigration department approves and issues it. Once approved, a copy of the visa, in PDF format, is sent to the concerned tour operator, and reflected in the online system.
Prospective tourists pay the minimum daily tariff of USD 250 during high season, and USD 200 in regular season per head, which has to be deposited with TCB’s account. Tour operators can then access the online visa system through their user accounts with TCB.
After tourists leave the country, TCB deducts USD 65 a day as royalty during high season, and USD 55 for regular season, plus two percent as tax deducted at source (TDS). The remaining amount is transferred to the tour operator’s account."