I dont have the Expanse but based on its description it would not be necessary to use both per se, although i guess you could put The Expanse first in the playlist to like open you and your systems up to receive and resist receiving more energy from the audios that would follow and then Acu at the end to still help the energies distribute evenly and smoothly.
Plus Acu just have other additions or mechanisms that help round the whole process in a harmonious way for your body.