While sitting in a blind chair/stool, I've noticed my groups have shifted down and to the right compared to when standing? What am I doing wrong?

Horizontal or out of a tree

horizontal

Different anchor points.

Pretty much is always going to be your anchor point or torque from the hand holding the bow. Most people teach to concentrate on grip and your anchor point. I think it is important to use 3 points of anchor: anchor point at jaw, grip and one other (I use my nose and the string). Creates a triangle and I can almost shoot from any stance and keep consistent. Main area I have an issue with is shooting to my right (I am right handed), shooting to my left is easy. Few people practice this shot, but hunting trees, I have found a need for it.

Most people I have seen having an issue shooting from a sitting position compared to standing is their grip. Typically, the bow ends ups canted to one side or the other. Make your draw and focus on the level of the sight.

Good luck

X2

Practice both... I have a tree in the front yard I put a lock on stand to practice with....

Thanks fellas.