Thank you for very good answers to my question.

Just wonder what is the use of output AUX A1,A2,A3,...,A16.

Who needs more than one output?
Or is this just for mixture of final output mixing effects.

What is the use of subgroups?

Mixer Tracks ==> AUX1 TO A1 ==> AUX A1 Output
AUX 1,2,3,...,8 x 8
AUX A1,A2,A3,...A16 x 16 (output)


Thank you for your time
B