There is a logic to op-up rules, if CX made it too subjective it would be a mad house. Many reasons why Jane would be passed over. Perhaps there was DM booking-linked with his colleague, with lower BN, and CX op-up them together. Perhaps there are families op-up together. On many TPE routes my wife (GR) and I (DM) were op-up together, to the other DMs that didn't get upgraded they may wonder how can my wife be op-up with only GR.

Empirical evidence (myself) suggest I get so much op-up ever since I made DM, and as DM + BN1 and overbook I haven't been passed over yet for an op-up.