Determining household size for I-864 and I-864A

[Nelly_M 7]

Hi guys,  I need some clarification on determining household size in case where petitioner has no income and lives with parents who will be used as co-sponsors.
Both parents are retired, and petitioner has recently moved to US and is looking for a job. My understanding from reading some threads on this form is that petitioner/ main sponsor cannot list their household members income on I-864 if he/she has no income to combine. Instead, one of the parents will be joint sponsor combining income with their spouse. Therefore, petitioner and joint sponsor should each complete I-864 while the other parent should complete I-864A to ensure their income is combined together (they file taxes jointly).
 

Having said that, what is the household size that each should be reporting on their forms respectively?  I understand that petitioner should include himself/herself plus the immigrant spouse, but what about sponsoring parents? Are they included in main sponsor’s household size count and vice versa? 

Thanks in advance. 

[Lil bear 4,218]

Moved to IR1 “process and procedures”