Pandora items with experience are still more valuable than Pandora items with gold. And that Pandora item with 15,000 experience was worth 18,000, which averages out to 31 Djinns.
I have updated the program using the old link (i.e., the link from the first post now contains the new version): http://yadi.sk/d/Lg48jhvZ2BoJg
In addition to the error with the Pandora items in the text file, I also fixed a small bug in the program itself: when the number of cities was changed, the label with the total value of the group of objects was not updated.