Section 5
SEC. 5. Section nine of Republic Act Numbered Eleven hundred and sixty-one is hereby amended so as to read as follows: "SEC. 9. Compulsory coverage.—Coverage in the System shall be compulsory upon all employees between the ages sixteen and sixty years, inclusive, if they have been for at least six months in the service of an employer who is a member of the System: Provided, That the commission may not compel any employer to become member of the System unless he shall have been in operation for at least two years and has, at the time admission, if admitted for membership during the first year of the System's operation at least fifty employees: and if admitted for membership in the following year of operation and thereafter, at least six employees: Provided, further, That any benefits already earned by employees under private benefit plans existing at the time of the approval of this Act shall not be discontinued, reduced or otherwise impaired: Provided, further, That private benefit plans which are existing and in force at the time of the compulsory coverage shall be integrated with the plan of the System in such a way that where the employer's contribution to his private plan is more than three and a half per centum he shall pay to the system only the three and a half per centum required in the Act and he shall continue his contributions to such private plan less the three and a half per centum contributed to the System so that the employer's total contributions to his private benefit plan and to the social security system shall be the same as his contribution to his private plan before the compulsory coverage: Provided, further, That any changes, adjustments, modifications, eliminations or improvements in the benefits to be available under the remaining private plan, which may be necessary to adopt by reason of the reduced contribution thereto as a result of the integration, shall be subject to agreements between the employers and the employees concerned: Provided, further, That the private benefit plan which the employer shall continue for his employees shall remain under the employer's management and control unless there is an existing agreement to the contrary: Provided, finally, That nothing contained in this act shall be construed as a limitation on the right of employers and employees to agree on and adopt benefits which are over and above those provided under this Act.