That is 21 years later and she has decided Hansson will be her name in America.
The only way she could have been born -sson, is if her father had frozen his patronym to a family name before she was born in 1870 and then it would have been his patronym, Bengtsson, and Jennie/Johanna would have been born Bengtsson. Also, 1870 in the rural south of Sweden, it was too early for that. So she was definitely born Hansdotter. It could definitely not have been Hansson.