I am aware of the discrepancy concerning the children of George and Martha Potter. There is a family story somewhere that talks about six Potter brothers, who came to America but went in different directions. However, the only information I have ever been able to find stated that Nathanial Potter was not a brother to Robert and George, thus not a son to George and Martha, and that Susanna was Nathaniel's sister and that their parents were Robert and Elizabeth (Marshall) Potter of Newport, Pagnell, Buckinghamshire, England. This information also states that Nathaniel is actually a brother to George, the father of George and Robert.
My personal family information goes no farther than Nathaniel, so I really have not pursued any information past George and Martha,which puts me at odds with my brother-in-law who is also doing genealogy research and insists that the George and Martha connection is correct. However, I don't believe he has any records that support this.