Maybe my android version is too old or it is due to Samsung's android, but I have to admit I actually don't have this button natively on a Samsung galaxy note 10.1 2014 edition. So I am happy that you added it for both.
I can confirm changing a subitem works (v6). However, I didn't manage to get the numbered list to continue. Pressing enter twice doesn't work to get back to default level (I guess this wasn't implemented) and if I change the indentation with the according toolbar button, the unordered list button stays selected and trapped in this state. Additionally, if I change the indentation of any ordered list element it's number doesn't default to 1. (only if I switch it to unordered and back to ordered). I'll try again tonight and will test more of the functionality.