By default, the Series III mixers do not deliver any processing to the 16M. The 16M receives the pure "pre processed" signals, whatever the source is (input channels, auxes, subgroups, matrixes). But for all of them you have the option to
set "Digital Send Options" to "Post", which sends all signals processed to the 16M. Now you hear what has been done on the mixer...
UC_Surface_ReferenceManual_EN_24042018, section 2.4 "Mix Detail" to section 2.5 "Mix Settings View": "Digital Send Options (Series III only). Mix outputs can be sent to the audio network or the USB bus pre- or post-fader. The postfader option includes all GEQ and output delay settings."
You can find the same option for input channels, auxes and matrixes.