Genesis 35:22-26 Meet my sons

"...Jacob had twelve sons:
The sons of Leah:  Reuben the firstborn of Jacob, Simeon, Levi, Judah, Issachar and Zebulun.
The sons of Rachel:  Joseph and Benjamin.
The sons of Rachel's maidservant Bilhah:  Dan and Naphtali.
The sons of Leah's maidservant Zilpah:  Gad and Asher.
These were the sons of Jacob, who were born to him in Paddan Aram."
                             (Genesis 35:22-26 NIV)

These verses are a summary of Jacob's immediate descendants.  They are all said to be born in Paddan Aram.(v.26)  However, Benjamin was born in Canaan.  Since that fact is evidently known to the writer (because Benjamin's birth is chronicled in this same chapter), there must be some reason why the twelve sons are lumped together in this way.

•   It is probably recorded in this way because Jacob is now back from his journey and the list of sons shows how God has blessed Jacob (who left home with only his staff) while he has been away.  Since Jacob is not yet 'home' to his father Isaac's tents, I guess Benjamin's birth is included in the summary of Jacob's journey.  

• Also, since Benjamin had probably been conceived in Paddan Aram before his family left Laban's household, it could actually be said that Benjamin 'began' in Paddan Aram!