Each page sum function can only be used once in a report. Using it multiple times will result in wrong calculated values!
Demo
//This function belongs in a PageFooterSection of a telerik report
=PageExec("textBoxValue", //put in a textbox from your table row. Typically your value textbox, but whatever is in your row will work. This triggers the accumulation of the values
BrixxPageFooterSum(
Fields.yourValue, //put in the Value Field you want to sum up
ReportDefinition)) //this is fix (it will tell the sum to reset for each new report)
