Maybe he was trying to derate for that seriously packed looking conduit on the bottom? Wonder what happened to the insulators for the left breakers bus bars?
So to fix his complaint did you turn off the breaker on the left and turn on the right one? Use breaker locks?
Or you could flip flop the service wires to each breaker and leave them on and off like they are now. The one tenant would not know what is going on when he gets his bill.
Easyest change the numbering on the meters.
No one said anything about the missing bushing on the bottom.
If I wanted to steal power from a neighbor or the landlord, I'd move only one of the two hot wires. Less obvious that the theft is happening, as consumption still shows on my meter ("I'm conserving energy") and the victum sees only a milder increase.