Typically, a meter base on a single family residence is not at the load side of a disconnect, but I have heard utility stories. The code does not specify where it goes, but 230.82 allows it on the supply side of the disconnect. The question at hand is if the disconnect can be ahead of the meter base, and that would be up to the utility. I see other potential problems with the installation for which there are not enough details. The review of 240.21(B) would seem to be in order to answer the vagueness. Also, what is "heater bonding"? The grounding would have to take place at the 400 amp disconnect. The equipment grounding would have to begin there also. But, what do you do with it when it goes through the meter base? That is what it is supposed to do. The meter base may have a "tickler" wire that is connected to the grounded neutral termination. Also, the meter base is typically bonded to the grounded neutral termination because the neutral termination is bolted to the housing. But, wouldn't that make the meter housing part of the current carrying grounded circuit? I would think so but it is allowed in 250.142(B). This is typically used when there are more than six main disconnects that are fed after meter enclosures and a main has to be implemented before the individual unit metering. Hope I havn't confused the issue tooo much, but I hope I answered the question.