To answer your question, yes, the Flow 8 can send 4 separate tracks to your computer.
I did a quick peek at the Flow 8 and it looks like it has to be set in "Recording mode" for the Flow 8 to send the 4 individual channels via usb.
When the Flow 8 is in "Streaming mode" it will mix all the channels to a (2-channel) stereo track and send that via usb. (which is what you don't want).
I already saw a few youtube videos about the Flow 8, watch a bunch of them, especially if there's one about USB recording. I hate reading manuals, but when I get new gear I try to read/peruse the manual at least a couple times and watch a few youtube videos before trying anything with it.