Remember a 10-75 is a request for assistance.
A 10-75 was a request for 3 & 2 & 1 Batt.
All Hands (75) means:
1. Using 3 & 2.
2. Using 2 & 2 plus a squad.
3. Using all personnel on scene. (This could only be 1&1 or 10&10.)
Squads only went on boxes normally assigned. MOST of the boxes did not have a squad assigned.
Rescues were assigned either on 1st, 2nd, or 3rd alarms.
There were no mandates of having a rescue or squad on all boxes.
After the war years, there were no squads for a good number of years.
There were boxes in almost all the boroughs that on the 1st alarm was only 2&2. The second alarm was 4&1.
No 10-75 battalion chief. Only 1 additional batt chief assigned on the 2nd alarm & that was it.
So yes, you could have had a 5th alarm with one deputy chief & 2 battalion chiefs.
There were boxes throughout the city that had 2 battalions & a deputy on the first alarm.
Now the alarm assignment levels are standardized citywide.