Very nice DIY - Froop!
You might want to recheck your trans fluid level when the trans fluid is fully warmed up. I think bmw says to check it at 80'C. So when you add new fluid, you really need to have the engine/trans running a long time. ~45min.
Also... since you were only able to replace ~5L of ATF... you might consider another ATF fluid change(w/o changing the pan filter). I know when I changed my ATF on my e39 it took a few trans fluid changes before my ATF looked nice and red coming out(old ATF) of the pan. Its so simple to do this job, it boggles the mind why BMW does not want us changing our ATF fluid.