I arrived in LAX last week in the afternoon around 2~3pm and did it there. You might have to wait a bit since there's only 1 counter and the officer might not be there. Let the immigration officer know you are conditionally approved and get directed to the right counter because the people directing the queue don't care if youre doing global entry or not. Think the right counter was like counter >50 or something. The rest of the counters are general immigration.