Ease up brother, we seem to be going back and forth between posts. What I posted was that he had a 320 amp service. The actual UL listed meterbase mounted to the wall, that will accept a socket meter is rated at 320 amps continuous duty, unless it is a K base, or bolted meter, which is rated at 400 amps.
http://milbankmfg.com/products/ResMeterSockets/index.asp A 320 amp meter base used for a 400 amp service is being asked to supply energy at 125% of it's listed continious duty rating. If a meter base is rated at 150 amps, can it be used for 187.5 amps continious duty? That is 125% of it's listed continuous rating, just like the 320 amp meter base being asked to supply a 400 amp service.
Although the nomenclature is used interchangibly, a meterbase that is rated at 320 amps is simply not a 400 amp service in my opinion. Now for the fun part, can a 150 amp main be used behind a 100 amp meter base?can a 200 amp main be used behind a 150 amp meter base? Can 2-200 amp mains be used behind a 320 amp meter base?