(a) The cost of money for an asset shall be calculated as follows:

(1) The cost of money rate used shall be based on interest rates determined by the Secretary of the Treasury pursuant to Public Law 92-41 (85 stat. 97).

(2) A representative investment amount shall be determined each cost accounting period for each capital asset being constructed, fabricated, or developed giving appropriate consideration to the rate at which costs of construction are incurred.

(3) Other methods for calculating the cost of money to be capitalized, such as the method used for financial accounting and reporting, may be used, provided the resulting amount does not differ materially from the amount calculated by use of paragraphs (a) (1) and (2) of this subsection.

(b) If substantially all the activities necessary to get the asset ready for its intended use are discontinued, cost of money shall not be capitalized for the period of discontinuance. However, if such discontinuance arises out of causes beyond the control and without the fault or negligence of the contractor, cessation of cost of money capitalization is not required.