Sorry I will try to explain better. I can only make a tiny overbite if my lower jaw is forced backwards. This is compounded by my maxilla being impacted by the surgery especially toward the back of my bite. This means I have to bite quite deeply to get molar contact and most of the bite pressure is in a horizontal direction. The lower incisors are forced into the back of my upper incisors since my jaw joint is being forced out of its range of motion.
When I had the upper removable retainer wire putting slight backward pressure on the upper incisors and the opposite from the fixed retainer wire on the bottom, I could not make a bite.
The bite I have now relies on movement of the teeth, the uppers forward and the lowers inward, retainers did not allow this since they locked the teeth into position.