This thread got me to thinking . . . again . . . not a good thing.
Back in the 70s during my BR efforts I got fed up with mirage. Went to the range before sun up. Zero'd the 40X 222 light rifle. I think it had a 20 something power Leuy on it and a 2oz trig.
Wind was always from the same direction. The only differences were in intensity.
Long story short. I shot 1 shot every half hour. Adjusted left or right for wind. Held on center vertical for each shot.
From 6:00 AM to 10:00 AM POI moved up 1.5 MOA. I was pretty proud of myself as the sting was a straight vertical line. That morning helped me win a bunch of matches on "that" range.
If you are consistently shooting low due to mirage that tells me you are shooting with the wind going from you to the target. This pushes the target image down.
I read the attached discussion from time to time to keep me from switching to thinking back wards.
Remember, mirage is your friend! . . . . once it's understood.
Also, one season I watched a muley that looked like he was painted on a sheet hanging on a clothes line. Only happened once. I didn't take the shot.