How could 35SE be HAST? I don't see that jumble anywhere in the relevant excerpt between the two surrounding jumbles. Mind you, my brain is so addled from looking for jumbles that I could have easily missed it.
I'm quite puzzled by that preamble reference to resolving an ambiguity. I have the highlighting and I cannot see any ambiguity that hasn't already been resolved by the excerpts. I didn't have to change anything to get the correct milestone, so have I been lucky and opted for the right choice out of two possibles without realising there were two possibles?
5SE gave me endless grief. There's another more obvious possibility that recurs throughout the texts where that clue is jumbled. To anyone who hasn't yet finished, if you run into problems in that area of the grid check 5SE carefully.