The electrician monitored usage and come up with 30A/42A/52A on each of the phases at peak demand. He's balancing the loads to be more equal but even he mentioned that he would like to see more amps available.
I've been thinking about the ground jumper bar. If you remove the bar and there is a ground fault. Is the breaker that would trip be where the ground and neutral are bonded? In this case a different inaccessible basement.