If the 10-75 is given and chief is asking for above that assignment, it is taken that "all hands are being used". Definition in communication manual for all hands is 3 engines and 2 trucks going to work. 10-75, 4 engines, 2 trucks, Fast truck, Rescue and Squad. Go extra 1 & 1 above, equal 5 engines and 3 trucks (not counting fast truck), safe to give the all hands.
"New" procedure also, if dispatcher is loading the box, it is the full 10-75 assignment minus the deputy. This was done so that their was uniformity. No 10-75 has been given, but if you are the 4th engine or fast truck, your ticket says fill 10-75 due to computer. Someone still has to transmit it.
Also, probably in Dispatchers Directives, if "all hands" is given without 10-75, dispatcher will give balance of 10-75 assignment (or ask if needed), unless the probably will hold is given with the all hands.