this info comes from a local mexican friend, I am not sure if it is 100% right or not as my next stop will be to CFE to clear some problems I am having, as a normal rule CFE will only install one meter per lot unless you have rentals in the same location you live but as explained before will not do anything for your bill reduction, just separate the tenant bill part from yours, if you have a double lot then you have option to get a second meter, expensive, which will really help with lowering your bill as a whole, re-wiring for and existing home is the most expensive part unless it was built with that in mine, I know of a couple of homes built with that already in mind, large homes.