It is well recognized by the consumers and financial communities that the nameplate tolerance limit needs to be tightened. However, it is not known what is the practically acceptable lower limit to address the limitations of manufacturers, testing labs and standards developing communities. This paper aims to provide a data-driven objective evidence to support tightening the nameplate rating tolerance so the industry and standards developing organizations may consider requiring a lower nameplate tolerance. The independently measured Pmax data of thousands of modules, between 1997 and 2013, have been statistically analyzed to determine an acceptable lower limit for the nameplate tolerance. This extensive statistical analysis, based on the statistically significant number of modules, clearly indicates that the nameplate tolerance of less than 5% can easily be achieved by the manufacturers and is recommended to be included in the rating tolerance and pass/fail test standards.