Was Schumacher leading when he went off in Hungary '98?
Think so. He lost 5 seconds to Hakkinen but I can't remember if DC was still in the lead at the time?
Schumacher was already leading, and was trying to build the gap for his extra stop when he went off. The off track excursion did not end up costing him. In fact, once he took the lead in that race, he never relinquished it.
I have to say this was my all-time favourite race. As a fan, even I wrote off his chances early on in that race, and he made me eat my hat. I dozed off on the sofa, and shot awake when I heard Murray's surprise at his early 2nd stop, I remember thinking "This could be interesting". Even then I didn't think he would be able to build enough of a gap in one stint, at most maybe rejoin behind after final stop and close up near the end of the race.
I know the Bridgestone/Goodyear war had a lot to do with it, but that race was basically Brawn & Schumacher saying to McLaren, "We're going to start the game behind you, make an extra stop, overtake you without actually physically passing you, and there's nothing you can do about it".