They might be thinking that the mental exam will qualify you without a need for the medical exam. I was approved based on psychological issues when in reality, my problems are from a brain injury. The SSDI psychologist expert claimed that I did not have a brain injury. But, he did say I qualified based on his psychological criteria. They went with the strongest evidence.

If the mental exam shows you to be disabled per SSDI criteria, then there is no need for the medical exam. An approval is all you want.

You do not need it to be inclusive of your other symptoms too.