rodeored on "Do the instance ids change for each instance?"

I'm using the all in one calendar.
I originally assumed that each event instance would be permanently tied to a row in the wp_ai1ec_event_instances table, so therefore I could always refer to that night's particular show by the id of that instance. However that no longer seems to be true.

For example, when I first created an event, one particular instance had an id of 11. But after I created some other events with other instances, the id of what was instance 11 was now instance 1004.

Does that make any sense? Do the ids of already existing instances change when you add more instances? If that's true, how do I refer to one particular show? Isn't there some field somewhere that permanently refers to a particular instance?