Based on your PDF, the answer looks correct. Not sure where you're seeing 517,610, as the avg closing price on your report is 717,563. So,
is -2.07%, as displayed on the report. It does seem odd that the overall averages match the last detail entry. I can't match either of the overall averages using the amount totals and number of listings.
Having read your PDF I found that I gave you the incorrect information it is mathematically incorrect to sum averages and use this for calculations.
I found errors in your Totals in the Report Footer -
How can there be a total of 6033 listing when the actual total is 340, the same for your Listing and Closing amounts?
Using the sample data in your PDF I have attached a database and the report as a jpg. The report totals are correct. In the design mode of the report called rpt_listing have a look at my totals calculations.