My understanding is that if "calibrated" all the speakers with the SPL, then they all would be consistently higher - not just the sub.
If you have phase control, you may want to do some experimenting - perhaps setting to 180 if it was at 0. If you try that, you may also need to recalibrate.
If you have phase control, you may want to do some experimenting - perhaps setting to 180 if it was at 0. If you try that, you may also need to recalibrate.