GuilleGee

From my personal experience, this is INCORRECT. I was recently checklisted for my AOS having sent in an I-864 for myself, while my father (whom I am currently live with) sent in an I-864 for himself + and I-864A for my mother (they file Jointly). When I called in to get help to complete the checklist, I was informed that since I am currently living with them, I can include them in my "Household" and both will fill out I-864As and my declared household income will reflect mine + my parents. It seems ridiculous to me that they would checklist this, but I suppose I understand it. (See I-864A definitions of household member here: http://www.uscis.gov/sites/default/files/files/form/i-864ainstr.pdf, see relative bullet point)
I completed the checklist, and am now on about day 10 of waiting for a response. Hopefully will come soon, as my wife just returned to Argentina after a 1 month visit, and the next ticket we plan to buy will be her 1-way. When I receive a reply, I will update this thread, hopefully to confirm that this is correct information. I will also add this info to the WIKI (please remind me as much).