In today world of competition, one of critical success factors influencing survival, profitability, and competitive advantage of manufacturing organizations is to select appropriate maintenance policy. While decision making grid (DMG) provides a relatively comprehensive perspective to managers for policy making, its criteria does not include overall equipment effectiveness (OEE), perhaps since OEE is mostly used in one of the policies, i.e. total productive maintenance (TPM). In this article, the traditional DMG has been modified, in which the range of OEE has been estimated and replaced by one of the grid's criteria. A case study has been conducted in one of the steel manufacturing companies of Iran and data has been obtained and analyzed from 30 machines of the company. The major finding of this investigation is that although OEE is an indicator of TPM, its different values might suggest different policies in addition to TPM.