Originally Posted by krosero
I know in the late 80s you could earn points according to the ranking of a defeated opponent. For example, at the '88 USO Wilander got more for defeating the #1 ranked player (Lendl) than if he had defeated someone else. I don't recall the details but I'm certain wins were weighted this way for a while.
Do you know when that began (and ended)?
Bonus points seem to have been used since the start of the ATP computer rankings. Evans gives some details about this in his book about Open Tennis:
A player is awarded tournament points (that vary according to the amount of prize money and the size and difficulty of the draw(how many Top10 or Top20 players are entered)) and bonus points (for beating players in the Top24: 6p for a Top1-8 player, 4p for a Top9-16, 2p for a Top17-24).
Bonus points were used up to 1999, but their distribution changed with time. In 1988 the situation was as follows:
30 (1-5), 24 (6-10), 20 (11-15), 16 (16-20), 12 (21-30), 6 (31-50), 3 (51-75), 2 (76-100), 1 (100-150)
From 1990 an increased amount of bonus points were awarded, for beating players in the Top200.
While bonus points certainly made the computation of rankings more difficult, I think their elimination was a mistake on the part of ATP (WTA also abandoned bonus points a few years ago).