Actual cost means the price paid for acquisition of an asset where such is paid, and includes not only the purchase price paid at time of acquisition but also all necessary expenses incidental to acquisition or incurred in making it fit for use in the operation of business. Where an asset is manufactured or constructed instead of purchased, the cost includes materials, labor and all expenses incurred in designing, manufacture, construction and installation necessary to make it fit for use in the operation of business. In the case of an asset brought forward at the beginning of a period, the cost means the original inventory price.
Expense incurred in the expansion, replacement, improvement or repair of any asset as a result of which its value or efficiency is increased may, to the extent of such increase, be added to the balance of the actual cost for computation.