Hi,
in the billing summary for november it says 14 GB of UGC storage is used, but in the billing summary for december it says only 1 GB of UGC storage is used. In your UGC billing example it says that downloading images or content only counts into the UGC requests meter.
So where does this difference in UGC storage usage come from? Were 13 GB of UGC deleted by the users or does only newly created UGC count towards the UGC storage meter and/or are downloads counted into the UGC storage meter?