Complex sentence: Scoring for this round was 1-20 (10-20 after Mohr took over), and instead of this round's prize going to the winner of it, it was the grand prize and went to the high-scoring team of the day.
Split into simpler sentences: Scoring for this round was 1-20 (10-20 after Mohr took over). Instead of this round's prize going to the winner of the round, it was the grand prize and went to the high-scoring team of the day.