From the same source: "In the previous nine bull markets the peak reading in new highs was always well before the eventual peak in the market and in five of them even before the half-way point."
However, keep in mind that the guy highlights that "more stocks need to follow the index to new highs before they get fully bullish." And, "what's important as the S&P 500 closed around new highs, is how many stocks made new highs."