Wow, 70fps!! I'd expect to see a 1 inch drop at 55 yards from that. Surely a false chrono reading? It certainly sounds like it to me.
The things being described here are all familiar to me though. Mine used to do the same things. Fortunately, Neil has superior technical knowledge to me and was willing to take my FTP on face value. I believe he ended up doing very well with it. A man of patience and understanding was what was required, and I have little of either.