Fleet Arena - 100,000 + crew power and still lose to identical fleets

For the longest time I ran a 4 ship arena fleet
Home One;; hmf, HT, Biggs ;; Bistan uwing
In fact, as long as Biggs was Frontline, I could reinforce any of the others and still have high chance to win. Total power was well under 300k total power and I breezed to rank 1 every night.
Wasn't unstoppable on defense by design; I don't need to be rank 1 all day, just when my rewards are dispersed.