Without context, chatlogs are useless. Go into more detail. What were you wielding. What were you hitting for without the disc active?
Edit: Nevermind. You were afk so I kicked you offline and found out myself. Enjoy the buffs.
http://pastebin.com/K6i96DLw
This is using a T-Staff, without disc. What you're seeing is probably a side effect of lower melee damage overall.
http://classic-web.archive.org/web/2...cription&Id=14
It looks like if anything is wrong, the regular attack damage isn't being added to the bonus damage, but the posts stating that there is addition look like conjecture with no evidence to support the theory.