Probably just an error in the chart, (or my brain), but isn't the Ping 4 arc inside Ping 1 Arc - roughly -29?
Sorry, my poor labelling; '-' in the legend means 'minus'
So Final ping arc = 00:11UT
Ping arc - 1 = 22:41 Ping arc - 2 = 21:41
Ping arc - 3 = 20:41
Ping arc - 4 = 19:41
I didn't model the pings at around 18.30 as it is not clear how they relate to the final constant speed route.