In 1964 or 1965, the first takedown of the match was 2 points and the remaining takedowns were 1 point. I don't know the reasoning for changing but I think it only lasted one year. I think it had something to do with taking your opponent down and letting them up. In those years, a win in a dual was 3 points.( no 4 or 5 point wins).
Les, you are correct, letting your opponent up to keep taking him down was considered unsportsmanlike conduct.
An old wrestling saying " You can pin people you wouldn't otherwise be able to beat". We have all seen it happen.