67. Delayed Refund.--
Where a refund due
under section 10 is not made within the time specified in section 10 from the
date of filing of [1][refund claim], there shall be paid to the claimant
in addition to the amount of refund due to him, a further
sum equal to six per cent per annum of the amount of refund due, from the date
following the expiry of the time specified [2][as aforesaid] to the day preceding the day of
payment of refund:
Provided that where there is reason to believe that a person has claimed the
refund which is not admissible to him, the provision regarding the payment of
such additional amount shall not apply till the investigation of the claim is
completed and the claim is either accepted or rejected.