Correction. Dot damage reduction was implemented september 13th 1999.
relevant link:
http://www.tski.co.jp/baldio/patch/19990913.html
It was then taken back out for no damage reduction on July 24th, 2002 (a few months before planes of power)
relevant link:
http://www.tski.co.jp/baldio/patch/20020724.html