Switchgear breakers do have adjustable settings to account for surges in current.... Sort of a hierarchy to keep an order to account for excessive current loads. For example: if you have to breakers, one 400 amp breaker and one upstream is a 500 amp breaker, they are, load wise, too similar and may trip together, creating havoc. We had a very similar issue at the hospital where the electrical contractor did not follow their own contracted study and did not "set" the switchgear breakers correctly. Until the correct settings were in place, we had operating rooms and essential equipment affected by shorts in lighting circuits. So, it is "possible" he is telling the truth about his "hit in the gut" feeling. We may never know if it was because of a breaker setting or an order from above.