Hi Hayley ,
No, it means they use the same priority in the menu list, and one replaces the other.
However, you should still see the ATUM menu at the top if it is activated (ATUM Settings .> Enable Admin Bar Menu). Do you see it?
If so, you can access all the ATUM options from there. Changing the menu order would require some coding skills (and us to add a filter hook). Please, let us know if you are interested.
Best Regards,
José Andrés