This is one of the things holding Studio One back from being considered a serious alternative to PT.
If I mixdown subtracks, say for example a whole bunch of tuned vocals, to save on CPU, it directs that track out to main. Not only that but it drops the volume.
So every time I mixdown, I have to reroute it via the bus again and volume match. Luckily your default levels are set properly, so if I hit "increase volume" it will increase and that level is the same as the previously mixed down track.
But come on guys, I shouldn't have to do this, this is silly. This also causes a UX inconsistency, because when I select "create bus for selected tracks" on subtracks (for example, a bunch of toms, or a snare sub-bus), it will still route out of that parent bus i.e. the drum bus. So this is good, it just means you need to reflect this type of behaviour across mix-down functionality as well.