Excuse my ignorance (not just on this topic, but everything else too).
I noticed recently that having been shooting in Tv mode with a +2/3 EC, I must have changed some setting where it obeys the EC setting in Manual. Not full manual obviously, but when using auto ISO. So for instance if I shoot at 1/500s, +2/3 EC in Tv mode, then switch to M mode and set 1/500s, f/4, auto ISO, the +2/3 EC still remains and it adjusts accordingly. Previously, when I switched from Av or Tv mode back to M mode, the EC bar was never there and I couldn't do it. I wonder what I did? I'll check through my settings more but could it be from the newest firmware version where you CAN do EC in M mode and I just didn't know it? Thanks.