Review other settings in the reports, such as soft credits, matching gifts, filters, attached queries, Gift types, General tab (especially pledge type of Master / Installment), etc. If split gifts are present, then each split counts as one gift in both reports.

For example, if Bob Smith has given a gift for $10,000, and the gift was split as $5000 to Annabell Johnson Endowment, $3000 to Camp Kids, $1500 Library Furniture, $500 to Computer Lab funds, each portion of the split will show as a separate gift on these reports as opposed to one gift for $10,000.