This is one of the few PS3 game lead where the 360 version is noticeably inferior. My guess is that this is a legacy of the PS3 exclusive era of coding during FFXIII's development, making porting a bit harder than starting from scratch with both console in mind... and space limitation of course.
Generally speaking, 360 port of PS3 do pretty well and in some case even better than the PS3 version (Ghostbuster >.>)