With Mary, there is no problem with her calling Jesus "Saviour" after He prevented her from falling into the pit of sin by granting her the wholly gratuitous and unmerited grace of an Immaculate Conception. But for grace, Mary, like the rest of us, would have been a sinner. She was just prevented from ever being subject to original sin at all, whereas all of us have to be rescued from it. But in no sense does Mary need a Saviour less than we do, even as the Theotokos.
Would you be kind enough to explain this more fully for me? I am confused by your words above.