When you move a device to a new group, the device has access to the data quota of the new group.
However, this new quota is in addition to any data the device has consumed previously within the month you move them.
For this reason we recommend that, where possible, you move devices at the beginning of a Cycle Period. Otherwise, you could be providing a significant data allowance to an individual device and risk incurring mobile data costs due to it using Data Quotas from two Groups in the period.
The result is that Mark’s iPhone can now consume 12GB during the month before being restricted or cut off (2GB from it’s time in the Marketing Group and up to 10GB allowance within the Management Group).
If your group has a daily data allowance limit (as opposed to the default monthly limit), this event is limited to just a 24 hour period so should be less of a concern.
Reports will show the data used by the device in both groups during the month in which they were moved.