There is a revenue recognition report generated for the specific dates, BA was of version < 6.0.9 when the report was generated. Later, BA was updated to 6.0.9, all the available hotfixes installed. The revenue recognition report has been generated for the same dates as earlier, but the values in the reports are different.
The fix of #PBA-77390 ("Deferred Revenue Report and Revenue Recognition Report contains taxes") is included into BA 6.0.9 hotfixes. Since the date of the hotfix installation the values in the deferred revenue report and revenue recognition report do not contain taxes, which explains the difference.