Ah. Because it is a through flight, it only lists the departure for IAd and the arrival at HKG. For today's UA 899, the scheduled departure and arrival are the following:

Dep IAD at 0830
Arr LAX at 1055

Dep LAX at 1233
Arr NRT at 1555

Dep NRT at 1800
Arr HKG at 2140

there could be changes to the schedule. But, it should not be that different.