Foreign tax credit limitation: excess treaty or territorial credit ignored if it exceeds domestically admissible credit; carryforward period extended. Where tax credit allowed for income-tax paid in a foreign country or specified territory under treaty or unilateral relief exceeds the credit admissible against tax computed under other provisions of the Act, the excess shall be ignored when computing the tax credit for deemed income; additionally, the period for carrying forward unused tax credit is extended from ten to fifteen assessment years, effective from the stated commencement and applying to the relevant assessment year and thereafter.