I have just played and beaten 2 rounds with maximum health and protection on all of my ships. I only got 74 banners and not the maximum I usually get.
I thought it was a fluke the first time it happened but after it happened the second time and my opponents fleet took 0 turns before I had won, I was annoyed. It's not scoring the correct amount of banners for a perfect fleet win any more.
On my 3rd fleet battle it was the same thing. I won with maximum health and protection on all my ships and it only gave me 73 banners that time!