HI there DrO !
I've run your Fan Chart from the Tree Apps, and I see Shirley Pirkle as your mom, and her father I see listed as Robert Buckler-129, and then his father is Thomas.
Unless I'm misunderstanding the question, in which case if we start at Shirley, her mother's father is Adam Schuhmacher-103 and HIS father is a Joseph.
Can you email me a screenshot or add one to this post?