New Photo Voltaic System

Next week will make two months we have had our 10 panel photo voltaic system. In that time - quite often I will look at the Bi-directional meter to get an idea of how we are doing. Today's readings are (to date) 250 kwh consumed and 332 kwh produced. BUT - today (for the first time) I went to the inverter and it says that we have produced 546 kwh !! We will get our first utility bill on the 25th or so at which time the guy who sold/setup the system will come out for a scheduled service call - but I thought perhaps one of you wise people here might have an idea why the numbers are so far off. Thanks