Good news. Second service took less than three weeks and didn't cost me anything because it was a re-repair.
Bad news. Second service didn't fix the flash problem. No flash illumination in commander mode, even from the builtin flash. SB 800 fires in SU 4 slave mode. Popup flash works in TTL mode, at least some of the time.
I'll take it back to the store where I bought it and ask them to try to make the commander feature work. They will tell me I'm an idiot or Nikon service is a bunch of worthless morons. Or both.
Relevant entries on service printout: "RPL FLASH PCB" "ADJ FLASH OPERATION"