Mike the NEC does not regulate how many meters are acceptable.
The number of meters is not the number of 'services' to the NEC.
One 'service' may supply countless meters.
The only hold up on using two 200 amp meters for a single 400 amp customer is the power company.
I recently remodeled a small retail space, when we where done it had three 200 amp meters and feeders to three 200 amp panels.
All one 'customer' and all 208Y/120 still only one service to this building.
