I can see how they are defensibly equivalent, but you'd never substitute one for the other. Also, 'doing sales' in the STEPHEN HAWKING clue somehow didn't create any kind of immediate association. That's just how my brain works, given lots and lots and lots of experience with these kinds of puzzles. So even after I get DAKOTA I expect that the second half of the answer will be a play on the word 'fanning'-not the Actual Word FANNING. That is: it's Wednesday, and there are '?' clues, so I expect wordplay. Weirdly, all the difficulty in this puzzle came from how unexpectedly straightforward it was.
Seems like an old concept, but it's executed pretty nicely here.
