Originally posted by jaden_2.0Spoiler:
No. Because those realities exist. In the same way they had to travel forward to their own reality after retrieving the stones rather than simply forward in time in the different realities they created by taking the stones in the first place they can also travel back to the correct ones to return the stones.
Spoiler:
They can jump back to where they came from, because they set the machine that way. But the impression I got is that they are not dimension hopping, but themselves creating new realities every time they go back to the past. Kind of like how the JJ Abrams Star Trek reality came into being.