Hello Andrew, Please read the response listed here in this KBA:
Also, You can add macro properties to the Jaspersoft report just like the following snippet on the text element properties:
<textField evaluationTime="Group" evaluationGroup="Group4" pattern="#,##0.00#;(#,##0.00#)" isBlankWhenNull="true">
<reportElement x="330" y="0" width="110" height="15" uuid="4d317c65-485d-49cf-bc80-155ce6703e2b">
<property name="com.jaspersoft.studio.unit.height" value="px"/>
<property name="net.sf.jasperreports.export.xls.formula" value="=SUM(C19:C71)"/>
</reportElement>
</textField>
Hope this helps!