You're right...when you add it up, the sauce prep takes about 15-20 minutes.
The steaks that they're having you use aren't incredibly thick, so when you drizzle the sauce back over them, that should help them recover their heat.
(you're also supposed to cover the steaks after you take them out of the pan, to help preserve their heat).
1 min per side is what most people use for getting a good sear with a very, very hot (blistering) pan and some good high-heat oil.
It sounds like, if you were doing 1 min per side previously with raw steaks, they were either very thin or you actually like your steaks almost blue, not rare. If you like your steaks that rare, I think you'll only enjoy using the sous vide for very thick cuts.