(a) Since he last became a member, and

(b) Prior to the completion of twenty-five years of service in such department, and

(c) Toward which he and his employer have contributed under this section, plus 4. An additional pension of one-fiftieth of his final average salary, multiplied by the number of years of service in such department prior to January first, nineteen hundred fifty-eight. This pension shall be payable only if such member has had one or more years of service as a member. The computation of this pension shall be subject to the further conditions that:

(a) The service shall be limited so that the service in such department used as a basis for pension credit under this paragraph four and paragraph three of this subdivision e shall not exceed twenty-five years, and

(b) The amount of the additional pension payable pursuant to this paragraph four shall not exceed the amount needed to increase the total amount of the benefits provided under paragraphs one, two and three of this subdivision e to one-half of the final average salary, plus 5. An additional pension equal to the pension for any creditable service rendered while not an employee of such department as provided under paragraphs three and four of subdivision a of section three hundred seventy-five of this article. This pension shall:

(a) Be payable only if such member has attained age sixty at the time of retirement and has not completed twenty-five years of service in such department for which he receives credit under this article, and

(b) Not increase the total allowance to more than he would have received had his total service been rendered in such department. f. The increased pensions to members of such department, as provided by this section, shall be paid from additional contributions made by the county on account of such members. The actuary of the police and fire retirement system shall compute the additional contribution for each member who elects the special benefits provided under this section. Such additional contributions shall be computed on the basis of contributions during the prospective service of such member which will cover the liability of the police and fire retirement system for such extra pensions. Upon the approval by the comptroller, such additional contributions shall be certified by him or her to the county executive of the county. The amount thereof shall be included in the annual appropriation of the county for the Westchester county parkway police force. Such amount shall be paid on the warrant of the county department of finance to the pension accumulation fund of the police and fire retirement system. g. In computing the twenty-five years of completed service in such department, full credit shall be given and full allowance shall be made for service of such member in war after world war I as defined in section two of this article, provided such member at the time of his entrance into the armed forces was in service in such department, and for service in time of war during world war I and service with the American expeditionary forces subsequent to November eleventh, nineteen hundred eighteen, and prior to June thirtieth, nineteen hundred nineteen, of honorably discharged officers, soldiers, sailors and marines who were actual residents of the state at the time of their entry into the military service of the United States. h. Upon retirement of any member pursuant to this section, any additional amounts credited to the member's annuity savings account pursuant to subdivision b of section three hundred thirty of this article shall be treated as excess contributions and shall be used to provide an annuity in addition to the annuity prescribed by this section. Any other amounts credited to the member's annuity savings account, except the amounts contributed or required to be contributed under this section and except such amounts as are required to produce the retirement allowance provided by subdivision e of this section, may at the option of the member of the time of retirement be withdrawn or used to provide an annuity in addition to the annuity prescribed by this section. i. The provisions of this section shall be controlling notwithstanding any provision in this article to the contrary.