If you have a Left AIC pattern with a right oriented pelvis and lumbar spine, with an upper spine above that orients toward the left (transverse), right ribs flexed left ribs extended (sagittal), and right thoracic abduction (frontal) why would you pressure the sternum more on the left lateral edge because that would help to further orient the spine towards the left transversely.
You need to clarify a couple of things to have your info completely accurate.
Most patients in this pattern are oriented towards the right throughout their entire spine, just less so across the upper thoracic spine. This right orientation comes in association with left upper trunk rotation (left ER inhalation ribs and right IR exhalation ribs). Because the left thorax is hyper inflated, the left border of the sternum is further forward and needs to move posteriorly with left rib IR exhalation of ribs- which turns the thorax back to the right (upon inhalation) on a spine that is being re-oriented back to the left (something that occurs during exhalation). This should explain the pressure on the left border of the sternum.