The South Region of Pemex Exploración & Producción (PEMEX E&P) is running a key development plan to improve the reservoir management, well productivity and ultimate recovery of all fields in the region. A fundamental part of this project is gathering reliable well production data on real time and on regular basics. The South Region of PEMEX E&P in cooperation with the technical team of PEMEX E&P performed a full study of available technologies in well testing to select a system that meet the needs of the region while simplifying the field logistic and minimizing environmental impact. PEMEX E&P selected the use of multiphase flow meters (MPFM). The program scope includes 8,064 measurements at well heads and collection manifolds during three years. The preparation and use of this MPFM program for multi-rate well tests was carried out with variable gas-liquid ratio flowstream and systems capable to measure all types of flow regimes in fields producing from heavy oil to gas condensates. This paper describes the lessons learned about the practical reliability, accuracy, and operability of the MPFM meters. The paper illustrates with field results the benefits of implementing the multiphase metering in the region. MPFM meters have proved to be a reliable system to measure well productivity.