The answered questions report should include information on discussions that were submitted as questions in your instance. For more information on the various reports available through the CMR feature you might find the Community Manager Reports - About the reports section of the Jive documentation helpful
Is the reason for this discrepancy that the report lists both questions or discussions? Or is something wrong?
It's possible that there is a sync issue with your reports, however to investigate this behavior further I would recommend submitting a case in your customer group here in the Jive Community so that the next available support engineer can examine your specific instance for further information.