Section 66B. Any domestic life company may purchase, lease, acquire by gift or otherwise and hold without any limitation of time any real property, or any interest therein, in any state of the United States in which it is authorized to transact business, in Puerto Rico, if authorized to transact business therein and in the Dominion of Canada where authorized to transact business therein and, unless approved by the commissioner, to the extent the cost or value of such real property together with the estimated cost of any proposed improvements thereon does not exceed, in the aggregate, three percent of the assets or fifty percent of the surplus, calculated as of the time such purchase, lease or acquisition is made, of such company, in foreign countries, and may use such property for investment purposes as well as any other real property owned, held or leased by it. Such company may use existing structures, may erect or cause to be erected new structures, may use any combination of existing structures and new structures, and may maintain, repair, alter, demolish and reconstruct such structures. Such company, alone or jointly with others, may manage, lease, mortgage, sell and convey the whole or any part of such property, and may collect or receive rents or income therefrom. No real property shall be purchased, leased, acquired or improved under this section if the cost or value thereof, or the estimated cost of proposed improvements thereon, or both of them, as the case may be, would exceed two per cent of the assets of such company, except as otherwise approved by the commissioner, nor if any such cost or value, plus the book value on the date of such purchase, lease or acquisition thereof, of all real property held under this section, would exceed fifteen per cent of such assets, nor if any such cost or value, together with the book value on such date of all real property held by the company, exclusive of real estate acquired for the convenient accommodation in the transaction of its business and real estate held pursuant to chapter one hundred and twenty-one A would exceed twenty per cent of its assets. The property shall be valued in accordance with the National Association of Insurance Commissioners Accounting Practices and Procedures Manual, unless modified by the commissioner as the commissioner considers appropriate.