979.10. Notwithstanding section 979.9, a market-maker is not required to include, in computing his income, an amount withdrawn by him from his reserve account for contingent losses to the extent that the amount represents the amount by which the contribution paid by him into that account in a taxation year, if he is an employee, or in a particular period that coincides with a taxation year or ends in that year, if he works for his own account, exceeds the deduction he is allowed to make in respect of that contribution under section 979.6 for that year, if he is an employee, or for that year or a previous taxation year, if he works for his own account.