
This is the report:

Note: The two hidden bands have "Calc Invisible" set to True.
I have tried various combinations of {Sum(DataBand3,lcp_items_total.Total_Cost)} or {Sum(lcp_items_total.Total_Cost)}, etc etc. Nothing seems to work. I know there is nothing fundamentally wrong. It's either incorrect use of parameters in the Sum function or something about the bands. It can't be this hard! And, yes, I have persused the Help documentatiion extensively.
Please advise.
Thanks