How many level in tasks?
In android application I see 4 levels: default, 1-3.
In web 5: default, 1-4. BUT level 4 I can set only for new task. When I try to change this task, or set this level for existing task, it automatically sets level 3.
This is uncomfortably sometimes. I set next level for task, but when I try to change this task's level it will be set to level 3.
There are 5 levels for a task: the default "not indented" level (parent task) and 4 indent levels. All these levels should be available whether you add or edit a task.
I've been able to reproduce both issues you describe - editing an indented task indeed puts it 1 level behind what you set it to and there are indeed 3 levels on Android. I've passed both issues to the developers and we'll address them soon. Sorry for the inconvenience.