Unable to create user

Problem/Motivation

Sometimes we wanted to be able to allow some users to add other users, but not change any user's password.

however when I enable this module and assign "Administer users" permission to specific role so they can create users - They are unable to add User name and Email.

Now I need to go back to role permissions and add "Change user e-mails" and "Change user names" so they can create users. However they can still change emails and user names and withotu that they cannot create user.

Am I missing anyhthing here ? I think there should be change user name and Add user name permission. So they can add but they cannot change.