The lawsuit raises an issue for FPL that started in 2002 when a Bradenton-based utility consultant named George Brown told the company that a particular type of meter it was using for its business customers was giving faulty readings. FPL allegedly uses thermal-demand meters for its 400,000 business customers. Brown allegedly told FPL that the "1-V" subclass of the thermal-demand meters were either overcalculating or undercalculating the amount of electricity that companies were using, and therefore overcharging or undercharging some of those consumers. FPL has since replaced 4,000 of the meters with newer digital meters.

In Spring 2004, FPL said that it would also be replacing two other thermal-demand subclasses, 4-N and 1-U, totaling another 16,300 meters. FPL has not admitted that the 4-Ns and 1-Us are in error, saying only that testing shows the two subclasses were "trending toward error." The action apparently alleges that the 4-Ns and 1-Us are in error beyond levels allowed by state law.

Landis Gyr, the world's largest meter manufacturer, stopped making thermal-demand meters more than a decade ago. The meters measure actual kilowatt hours used and use relative heat levels to make a measurement of peak demand. Only large electricity consumers were fitted with a thermal-demand meter. Most other utilities around the nation have replaced thermal-demand meters with more accurate and modern digital devices. FPL, on the other hand, allegedly still had about 90,000 thermal-demand meters in service at the start of 2003. The utility, which services about 450,000 commercial customers and 3.8 million residential customers, has said $1.8 billion worth of electricity, or 25% of its annual revenue, flowed through thermal-demand meters last year.