My recollection of the game play and bonus round is this:
Initially, it went 3 50's, 2 50's, 1 50; 3 75's, 2 75's, 1 75. After the 100x3 question, the player with the lowest score was eliminated. After the 100x2 question, the reminaing player with the lowest score was eliminated. When only two were left, you had to answer correctly first and be in the lead in order to win. Thus, there was no such thing as a mathematical lock on first. Later on, they switched the eliminations to the points mentioned in the article.
Initially, they had a different bonus round. If memory serves, you were given lines from ten different songs and had to come up with the next line. There was a fixed amount for each one you got right ($100, I think), and it doubled if you got all ten.
Later, they dropped the bonus round and just doubled the winnings. Sometime after that, they stopped doubling the winnings and added the bonus mentioned in the article.
Also, they occasionally had questions that were not simply, "What's the next line?" ISTR one where the question was, "Who had a hit with this song?" and the correct answer was Adam Wade.