Mine took 5 1/2 as well. Steady on the full mark when I changed it 4K ago. Now 'bout the thickness of a toothpick below full. With the B3000 filter going on next time, it'll probably be right at six quarts.
I leave 4 oz left in the sixth bottle and that puts it exactly at the full line and stays there until the next oil change. I went almost 6,000 miles on my last oil change and it didn't burn a drop.