Deduction for local property taxes tied to actual payment when owner bears the tax; prevents duplicate deductions. Where property is tenant-occupied and local authority taxes are borne by the owner, those taxes shall be deducted in computing the annual value for the previous year in which they are actually paid by the owner, irrespective of the year the liability arose under the owner's regular accounting method. If a deduction for such taxes was already allowed in an earlier previous year, no deduction shall be permitted in the year of actual payment.