Help FFXIII: Can I re-track back?

[Claire]

Alright, so I'm just now starting Chapter 12 and while I was in Sulya I happened to miss a few treasure spheres, I've gotten the rest all up until that point and after it as well. Is there anyway I can go back and get them for the achievement of getting all treasure spheres?

Thanks alot

 

[Rey]

Mhm ya in chapter 13 you will get warp gates one for gran pulse aand one for Eden. So yes you can. Also only 1 playthrough is needed to do everything. nothing is missable.

 

[Claire]

Alright thanks alot! I just happened to miss like 4 spheres, and thought I wouldnt be able to go back and get them.