Upon application, with supporting evidence, by the undertaking to the supervisory authority of the Member State in the territory of which its head office is situated and with the agreement of that authority ... where zillmerizing is not practised or where, if practised, it is less than the loading for acquisition costs included in the premium, the difference between a non-zillmerized or partially zillmerized mathematical reserve and a mathematical reserve zillmerized at a rate equal to the loading for acquisition costs included in the premium; this figure may not, however, exceed 3,5 % of the sum of the differences between the relevant capital sums of life assurance activities and the mathematical reserves for all policies for which zillmerizing is possible; the difference shall be reduced by the amount of any undepreciated acquisition costs entered as an asset ...