I thought the same, and I know that it was that way in the past, but on making enquiries to the relevant persons, I got this reply:-
"....if a British rider is lower with his discount than an overseas rider, the overseas rider will be number 1 until the first set of green sheets that the British rider gets a new average."
I think this interpretation/rule change only came into effect in 2023, as has been pointed out by others recently.