If any installment of compensation payable without an award is not
paid within 14 days after it becomes due, there shall be added to such
unpaid installment an amount equal to 10 per centum thereof which shall
be paid at the same time as, but in addition to, such installment unless
the employer files notice of controversion in accordance with
Sec. 702.261, or unless such nonpayment is excused by the district
director after a showing by the employer that owing to conditions over
which he had no control such installment could not be paid within the
period prescribed for the payment.
