Disallowance u/s 14A cannot be made on ad-hoc basis

Brief of the case:  ITAT Kolkatta held in Swew Benefit Company Vs DCIT that for disallowing expenses u/s 14A i.e expense incurred for non-taxable income, there had to be some logical strong basis like rule 8D or something else but it could not be disallowed on ad-hoc basis. If any authority was disallowing the expense incurred by the assessee for earning non-taxable income then that disallowance should made on proper basis not on ad-hoc basis. In other words only that part of expense had to be disallowed which had been utilized for earning that non-taxable income only. All expenses should not...