Thank you for your response Brian. If I understand correctly, you're saying the thing that makes it a "series" is the time of reporting by customer and really has nothing to do with transactions themselves.
I guess it makes sense. What was throwing me off, I think, was the "related" part; I don't see what purpose the word serves in that sentence, if the explanation is just that simple.
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"I was gratified to be able to answer promptly. I said I don't know." - Mark Twain