This reminds me of a conversation with a PHDd Electrical Engineer.
He said he had 120 amp service at his home, further questions resulted in 'two (2) 60 amp fuses'. His logic was 120 available amps at 120 volts. I wound up having my guys upgrade his service to 200 amp. He later was bragging that he had a '400 amp service in his home'.
Logic??
I think the OP here is going down the same path....
75 KVA, wye, 120 208 panel with the above logic is 600 amps at 120 volts.
