The wording on page 19 was left over from a prior version (before gc_retrip). When I next publish the documentation the wording will read:
4. If there are two (or more) events with the same event name and the second event has the same start time as the previous event end time:
If gc_retrip is set to true (the default): the second event is treated as a separate event. i.e. the plugin will trigger on the start of each event in the sequence.
If gc_retrip is set to false: the second event will be treated as an extension of the first. i.e. the plugin will only trigger on the first event in the sequence.