Any increase in pension payment received by any person under the provisions of this act shall be deemed cost-of-living increases, and shall not be construed as a permanent and binding obligation of the pension fund which will, in perpetuity, entitle¹ present and future pensioners to secure pensions predicated upon such increases. Such increased pensions shall be subject to revision by the General Assembly in the event of a decline or a rise in the cost of living. In no event shall any decrease in living costs result in decreasing the pension payments in effect prior to the passage of this act.