Where any barge in respect of which a tax for any period is payable or has been paid, is altered during such period as a result of which the capacity of the barge is increased in such a manner as to cause the barge to become a barge in respect of which a higher rate of tax is payable, the registered owner or the person who has possession or control of such barge, shall, in addition to the tax, if any, due from him for that period, be liable to pay for the unexpired portion of such period since the barge is altered an additional tax of a sum equal to the difference between the amount of tax payable for such unexpired portion at the higher rate and the rate at which the tax was payable or paid before the alteration for that portion; and until such additional tax has been paid, the taxation authority shall not grant a fresh tax token in respect of the barge so altered.
Explanation. - In calculating the unexpired portion under this section any broken period in a month shall be considered as a full month.