That's an interesting response from Delta. Last year, I had booked JAN-ATL-RDU, but the JAN-ATL flight was canceled. They rebooked me JAN-DTW-RDU (where I had to sit in the very last row of some crop duster en route to DTW -- painful, but grateful to be getting home). I only got credit for JAN-ATL-RDU and had to call to ask for the additional miles. I finally got them after a little complaining, but if one is supposed to get credit for what one actually flew, I don't know why it took so much effort.