Under PMUA, some of the two-segment one flight number flights were counted using "direct" flight BIS.

For example, my flight # UA890 in the late 90s showed SIN-DEN (9,048 BIS) rather than SIN-NRT-LAX-DEN (3,324+5,451+862=9,637)

There are other examples such SFO-SHA when UA did not fly to SHA directly from SFO ( it was SFO-NRT-SHA).