Differential Pressure (DP) Flow meters are popular for being relatively simple, reliable and inexpensive. Their principles of operation are relatively easily understood. However, traditionally there has been a misconception that no DP meter self-diagnostic capabilities exist and as such only upgrading to newer ultrasonic or Coriolis technology can help bridge this gap. In 2008 & 2009 a generic Differential Pressure (DP) meter self-diagnostic methodology [1,2] was proposed to the industry. In this paper these advanced diagnostic principles were applied towards helping provide end user a newer yet effective, methodology for DP flow meters diagnostics, field proven with experimental test results. These results form the basis of a comprehensive validation methodology designed to help meter operators achieve improved confidence on their DP measurement and thereby help lower their operational risks associated with large measurement uncertainties due to non-compliance. The paper also aims to demonstrate how such new advanced tools/methodologies can help reduce operating costs (OPEX) by moving towards a risk based predictive maintenance plan.