Co-sponsor or Joint Sponsor

[Artisan 138]

I have hit a snag and I want to check with those of you who may have experience. I currently live at the same address as my retired mother. I rent a section of the house from her and we maintain separate households for tax purposes. As my income is not quite enough to sponsor my wife on my own, my mother has volunteered to sponsor her. I was prepared to have my mother file as a joint sponsor but reading the USCIS instructions for I-864A seems to indicate my mother should possibly file as a co-sponsor instead. Any suggestions on how to proceed?

[Anh map 2,098]

Your mother can do an I-864A to help you make up a shortfall in income.

Co-sponsor is another term used in place of joint sponsor. It is the same thing.