12. Mode of payment of counting tariff, counting installment and
installment money:
(1) Where a contractor has undertaken to pay the money required to be paid to the Government of Nepal by the contractor in accordance with the terms and conditions of the contract in counting tariff, counting installment or installment, yearly installments shall be set by dividing the money to be paid into equal installments for each year on pro rata of that year and paid in accordance with the provisions set forth in sub-sections (2) and (3). The contract shall not use the amount until the  installment required to be paid pursuant to the said sub-sections is paid.
(2) Where a contract has undertaken to pay the money for contract as a counting tariff, the yearly installment to be set pursuant to Sub-section (1) for the first year has to be paid within seven days after the date of receipt of information that his or her tender or bid has been accepted and thereafter the yearly installment of each year has to be pai in advance of at least one month of the commencement of the year.
(3) Where a contract has undertaken to pay the money for contract as a counting tariff or installment, the money of yearly installment to be set pursuant to Sub-section (1) for each shall be again divided into four equal installments if the contractor is a citizen of Nepal and into three equal installments if the contractor is not a citizen of Nepal, and the first installment of the first year has to be paid within seven days after the date of receipt of information that his or her tender or bid has
been accepted and thereafter each installment has to be paid within the following time-limit:
(a) In the event of an undertaking to pay the money for contract as a counting tariff, the second installment of the first year and each subsequent installment in advance of at least one month of the commencement of the period of that installment, and
(b) In the event of an undertaking to pay the money for contract by way of installment:
(1) In the event of the contractor being a citizen of Nepal, the second installment of the first year within five months after the date of payment of the first installment, and each subsequent installment and other subsequent installment within three months after the date payment of the previous installment.
(2) In the event of the contractor not being a citizen of Nepal, the second installment of the first year within seven months of the payment of the first installment, and other subsequent installment within four months after the date payment of the previous installment.
(4) Notwithstanding anything contained in sub-sections (2) and (3), if a contractor fails to pay within the time-limit set forth in the said sub-sections the money of any other installment except the first installment and the last installment of the expiration of contract and requests for the extension of the time-
limit, the authority arranging the said contract or the prescribed authority may grant the time extension of a maximum of one month and the Government of Nepal may grant the time extension of a maximum of two months; and where the time-limit is so extended, the contractor shall pay the installment along with an interest by ten percent per annum for the period so extended.
(5) Where the time extension has been granted to the contract pursuant to Sub-section (4), a wealth guarantee shall be taken from the contractor for the installment in respect whereof the time extension has been granted and for the interest thereon as referred to in the said Sub-section except in cases where a guarantee has been taken pursuant to Sub-section (1) of Section 14. The contractor shall pay such a wealth guarantee to the authority arranging the contract or any other prescribed authority within seven days after the date of time extension