I am also descended from Amos Porter through his son Raphael. I think you have identified the wrong Amos. It appears there are 2 Amos Porters who served in the Rev. from Conn. and had daughters named Rachel. There is the Amos Porter who married Joanna Allen and an Amos Porter who married widow Amy Brewer Gaines. The 2nd Amos is our Amos, his father is Nathaniel Porter of Windsor who married 2nd Eleanor or Elizabeth Gillett. What makes it more confusing is that both of these Amos are descendants of John Porter of Windsor.
I notice that the reference in "The Kelloggs in the New World" to the parents of Rachel Porter is incorrect.
Hope this helps.