When an interpreter who has Mobile Access changes his password, it only changes the password for the Interpreter Portal.  Sorry about this.  We will get it fixed ASAP.  In the meantime, if they want the passwords to be the same, and the most likely will, you will have to synchronize the passwords for them.
Here is what to do:

On the main menu click Administration and then select Maintain Users.  Find the interpreter's account.  Unselect 'Mobile Access' and click 'Save'.  Then Reselect 'Mobile Access' and click 'Save' again.  
That does it.  What we just did was to remove the credentials for Mobile Access and then restore Mobile Access with the new credentials (and thus new password) that the interpreter just created.