The KP junction is at about 180.5 and the trailhead shows as 7 miles east.
Ahh, I see what I did... the 4.7 is only the miles from Kearsarge Pass to Onion Valley... NOT the JMT intersection (Duh... yah, I can read a map

), I didn’t add the additional miles to the JMT from the Pass.
But on looking at the map, I also have to wonder if part of the difference in my mileage charts is due to which of the three "intersection" they're using that lead to Kearsarge. I would have thought that the mileage charts would have used the most northern intersection (rather than the trail leading by Bullfrog Lake) but that may be the difference in the charts.