Correct me if I'm wrong, but I think you're confusing the Nightfightibg rules with some Necron power. The original Nightfighting is either ONLY on the first turn (decided with a 4+), or on any of the last turns, starting with turn 5, and then lasting until the game ends (BRB p. 124). Nowhere does it say that you keep rolling to see if the night stays, does it?
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