Different result in vCloud Usage Meter

Hi,

We have been using version 3.3.1 of vCloud Usage Meter for several months now.
Today we did a search for old months and the data is not the same as we got when we did the reports for the previous months.

For example:

During december we upgraded out vSphere from 5.1 to 5.5.

Any idea why we don't see the same result now as we did when the reports was submited to the aggregator?

Thanks in advance!