Data point: I called the UK number to convert my OC6 (870T) to a NC6 (QP99). Asked the rep if she can do that. She said yes and put me on hold, but when she came back she had converted it to a NC4 (QP83). I asked if it was not possible to convert to QP99, so she checked with her "US-based supervisor" and confirmed they cannot. No 30k points added to my account yet. Are there any datapoints of upgrades from a NC4 to a NC6?