Dead-eye: toggling the option to shoot multiple targets

Just what the title says:

Sometimes when I'm in dead-eye I can't seem to select to shoot multiple targets and other times it's turned on and I'm not wanting it.

Other times it targets automatically the person or animal as I am lining up the shot as soon as the dot makes contact with the body. Example: I'm aiming for a headshot but when it crosses them at the waist, arm, etc it puts a dot on that spot to shoot when I release it.

PS4 console