Nitpick much?
The reason the instructions don't say to put the ground tab back in is because you don't want to try to bolt the PCM carrier back into the bracket if you didn't cut a hole in the carrier. Yes, I realize that the instructions do not say to cut a hole in the carrier, but if you bolt the carrier back onto the bracket without cutting a hole (large enough for the entire back of the chip to poke through), then the chip will have pressure on it that can cause connectivity issues. THAT is why the instructions do not list putting the ground tab back on. I can only assume that Bill figured common sense would prevail when reassembling the PCM case so the instructions not telling people to reinstall the six case bolts may have been omitted. But then again, common sense isn't really common anymore.
I may make a few amendments in the instructions just to save some more frustration in the future.