Have you had it on a frame machine or had it aligned? I'm curious if there is any fundamental damage from the impact years ago that wasn't properly repaired.
Can I get close up pictures of the frame rails in the front near where the radiator support bolts up on each side?
I'm not the authority on SManger at all here, but I would suggest reading their documentation about the voltage vs the charts in Phearable. You could extrapolate between the two if you want to leave the SManager voltages alone, or you can adjust and test.
Minor suggestion here on that IACV. You can get OEM style spring band clamps instead of worm gear on Amazon for dirt cheap. I've seen so many worm gear clamps eat through the rubber over time that I'm not a fan of them.
Example here, but there are literally hundreds to choose from if you search ...