Alright, I asked another builder, inspector, and electrician and got varied answers (all saying this is wrong) but I need some help from the sparkies.
There was one meter on a 5,500 sq ft house - it was a service lateral. SE cable came in standard 200 amp service. Then (see the picture) on each one of the cables they tapped 2 wires off of them to two 100 amp breakers that were barred together (so 4 wires into what would be the main breaker). The they tapped a remote distribution panel off of the same entry point to feed a 100 amp breaker in the sub panel. Then I found another panel in the garage with another full 200 amps… but the owner had no idea where the power for that panel was coming from.
This was a one million dollar house (not that that always matters), and they had an inspection sticker on it since the panels appeared to be installed. Any guesses?