This is a passage from "Never finished" by David Goggins.
"I was hoping to find some answers that would help me change my life. That was what I told myself, anyway, as I crossed into Ohio from Indiana and veered northeast. I hadn't seen my old man in twelve years. It had been my decision to stop seeing him. At that time, the court system allowed children to make those decisions once they turned twelve. I made that choice mostly out of respect for and loyalty to my mom. He'd stopped beating us after we left Buffalo, but the one thing that never went numb was how I felt about what my mother endured at his hands. Still, over the years, I had questioned that decision and began to wonder if my memories, if the stories I told myself, were true."
I have two questions. (1)Why is the first sentence in bold not "He stopped beating us after we'd left Buffalo."? (2)In the second sentence in bold, why does he use past perfect for "question" and past simple for "began"? Is it different if I use past perfect or past simple for both verbs?