What you see is not always what others see. Your avatar will sit up to indicate to you that you’re getting a draft benefit, but the avatars of other riders will not do the same (and they do not see your avatar sit up when you do, but they would see theirs sit up when in the draft). Below certain speeds I think everyone is just sitting up.
The power is tough one because everyone seems to be constantly moving around in the pack, and because the draft is more prevalent on flat terrain, where actual watts are more important that wkg. So, you might see that you are in the draft but putting out more wkg than the rider in front of you (since the Riders Nearby list only shows the wkg), but that rider might be heavier than you, meaning he may actually be putting out more absolute watts (300 watts @ 100kg = 3 wkg while 250 watts at 75 kg = 3.33 wkg).