Let's assume SS get the same legs as BvS, 133.7 x 2 = 267M. OS it's already banked 192M, let's assume it will get the same short legs as BvS, 67% drop second weekend, so that's 133 x 1/3 = 44M, meaning SS will have 503M including total Dom and 10 days OS. Let's say the second week OS total of 103M gets big drops of 60% per week until the end of its run, which would be 41+16+6+2.5+1 = 66.5M, that makes it 503+66.5= about 570M. So it's already passed your higher end 550M estimate and wayyyy over the 500M estimate, and that's based on BvS legs or worse, WITHOUT Germany, Italy and Japan!
And BvS OS drop was huge because China pulled about 80% of sceens after 10 days, so the drop was worse due to that, but that factor don't come in for SS, but I still used the same legs for you.
So after this weekend SS will have about 240M OS along with 222M Dom, so that's 462M, it should get another 100M OS from here and 78M Dom, that's 640M, then add Germany, Italy and Japan, thus the 650-700M, if it ends up not having China.
SS has 17.8M on Sat, so all set for around 44M (basing on some estimates from BOT guys of course), and that means it's on its way to 300M, considering SP has a B, Pete's Dragon is dead unfortunately, and there are no big releases for a few weeks and Labor day is on the 5th weekend.