I had it work to my benefit. I was booked in J on a one way transatlantic for 62.5k. I called in to add the return now that it's bookable. Both segments are booked in O and ticketed (with seat assignments in J) and it dynamically priced my return as a low level COACH award. So, roundtrip in J for 92,500 miles. :-D :-D :-D