16. An operator may deduct as development allowance, for each fiscal year, an amount not exceeding the aggregate of the expenses contemplated in paragraphs m and n of section 8 incurred during a previous fiscal year that have not been deducted from the gross value of the output for that previous fiscal year, until those expenses have been wholly allowed.
However, expenses incurred before 1 January 1965 shall not be included in an allowance under this section.