I have HDFFL without autopay, but do have paperless billing. I know I don't have autopay as I have been late to pay on occasion.
When I set it up, the add said free HD for life. They told only if I set up auto pay. I said then it isn't free. I want what the add said. We went back and forth a few times, and I got HD free for life with no auto pay.
Some times it is annoying, sometimes it is fun, to negotiate a deal. Many years ago we would go to Tijuana MX and my wife would negotiate the price with various vendors for stuff she didn't even want, just for fun.