Nice tutorial. I made same steps when I was on 5.1.5.0G and I had same MzAccount app on my phone and root.
After I updated to 5.1.6.0G and lost root but had new User Center app and MzAccount app at the same time on my phone but only new User Center app was working.
Now I installed MzAccount again. After that I had only MzAccount app on my phone and User Center app disappeared. I restarted my phone made root (it's rooted now) but I have no MzAccount app neither User Center app on my phone. I tried to install MzAccount app again, it's installed but I can't find it on my phone. Even when I tap "Open" on after installation window, nothing happens.
Do you know how to fix it? Thanks!