Using the custom version of order-process.xml simulation, running 5000 iterations, it appears that not all generated tracking items are streamed to jKool server. The metrics printed at the end of the simulation run appear to show this.
Since each iteration of my custom order-process simulation generates 7 activities and 18 events, the total number of items that should be reported to jKool server should be:
7 * 5000 = 35,000 activities
18 * 5000 = 90,000 events
TrackerImpl/tracker-activities: 35,000
TrackerImpl/tracker-events: 90,000
SimulatedEventSink/sink-activities: 35,000
SimulatedEventSink/sink-events: 88,020
SimulatedEventSink/sink-skipped: 1,980
JKCloudEventSink/sink-direct-writes: 123,020
JKCloudEventSink/sink-sent-messages: 123,020