Upon its own motion or upon the application of any party in interest on the grounds of a change in condition, the Industrial Commission may review any award, and on such review may make an award  ending, diminishing, or increasing the compensation previously awarded, subject to the maximum or minimum provided in this Article, and shall immediately send to the parties a copy of the award. No such review shall affect such award as regards any moneys paid but no such review shall be made after two years from the date of the last payment of compensation pursuant to an award under this Article, except that in cases in which only medical or other treatment bills are paid, no such review shall be made after 12 months from the date of the last payment of bills for medical or other treatment, paid pursuant to this Article. (1929, c. 120, s. 46; 1931, c. 274, s. 6; 1947, c. 823; 1973, c. 1060, s. 2.)