It gets more bizarre... after checking all parts, resistors, caps, etc. around U7 and reflowing everything including U7 now I'm getting:
Sleeve to Tip: .360Vac
Sleeve to Ring: .723Vac
So now the right channel is louder or right centered. I've confirmed this with a few pairs of headphones. Looks like I *might* take the shotgun approach and redo the whole Gamma-2 section of the DAC. Another option is the pull all the caps around U7 and order them (I melted 'em) and another U7 first. I'd hate to redo U7 again to have to buy everything in the long run anyways. What a pisser!