(b)other assets, begins to be used for tonnage tax business, an appropriate portion of the written down value allocable to such asset shall be reduced from the written down value of the block of other assets and shall be added to the block of qualifying asset as per the following formula:—E= F x (G/I)where,—E = the appropriate proportion of the written down value allocable to the asset which begins to be used for purposes of tonnage tax business;F = the written down value of block of other assets as on the first day of the tax year;G = book written down value of the other asset which begins to be used for tonnage tax business; andI = the aggregate of book written down value of all the assets forming the block of other assets.