You probably need to define what you mean about the levels of moral development and whose establishing the level of moralness. Choices of right and wrong are not black and white. Right and wrong seems to fluctuate based upon societal norms, cultural norms and economic norms just to name a few. More clarification would help a better discussion.
I think the biggest thing to remember is that these are theory and they may or may not apply to all people. Most theorists try to stick individuals into specific categories and this is not always the case.
I will assume that you are asking about the levels of moral development that have been set out by the psychologist Lawrence Kohlberg.
These levels of moral development are useful to anyone who deals with children and adolescents. They can help a parent or a teacher understand how to deal with their children or students.
For example, if a parent believes in Kohlberg's theories, they will understand better how they must do things if they have more than one child. Kohlberg tells us that children are concerned with fairness above almost all else. If a parent understands and believes this, they will know that they must, for example, not give one of their children more Christmas presents than they give the other. This will be perceived as unfair and will make the child mad.
By understanding things like this, we can use Kohlberg's theories to help us in real life.