Well, upon further inspections its the CLIP volume key frames that are displayed in the Audio Effects area. When you are trying to do TRACK key frames on the timeline, its necessary to click on the SHOW KEY FRAMES icon at the start of the TL audio track. When you switch to SHOW TRACK KEY FRAMES suddenly the clip cannot be loaded in the SOURCE window (which kind of makes sense) and so the TRACK key frames are not visible for numeric entry.
So the problem with no ability for numeric entry assigning key frames a db still exists.
The best you can do is hold Shift while dragging a track keyframe; that forces slightly smaller increments in volume.
Yup, tripped across that one a while ago.
I just gave up on the track approach. Doing it as a clip approach is way easier. I just make the key frame, go the the audio effects window and enter the db level. Done. I did however put in a feature request to be able to right click on any key frame and enter a numeric that way. Im not sure how many other folks are going to request it, but I sure loved and needed that function in FCP and Avid.