error indicating I'm out of storage space

I just purchased a renewed Ipod touch Gen5 with 32 Gig of storage. I retired my old ipod and transfered my old Itunes music & play lists to my new Ipod no problem. I added a few more files to my Itunes software and added them into a few different play lists and went to make one final sync. But it failes telling me a need about 250 MB of storage space. I have deleted about 1 Gig of music and it gives me different amount of storage that is needed each time I try but it never works. I see on my Ipod I have 20 GB stored in music and about 6 gig free. Why can 't I sync my ipod with my Itunes?