Yeah, SC started as a side-project for Thomen and Piet to make music that sounded like old BG. He parted ways with BG during that side-project, so it became his main band.
When SC toured, Thomen had a nervous breakdown or something beforehand so Thomas Nack stepped in to do the drums for that tour (this was also why Thomen didn't come to ProgPower with SC). After Thomen got over that, they did another tour with Circle II Circle in Europe, but that was cut short because Thomen was having problems again. In the end, the rest of the band decided it would be best to let Thomen go and take care of his issues so they could carry on.
That's the basic gist of it, anyway.