In the example in Chapter 7 [page 104] we walk through adding an expression that is a calculated value on the line-item. The expression we calculate is (Unit Price * Quantity) - (Unit Price * Quantity * Discount). We put it in the Item Total field and it appears once for each line [Product ID] in the table.
There is a footer on the repeating table and a label for "Total:" but I do not see where Scott describes how to add a Sum() for the calculated value. I searched the help for InfoPath and it appears to skip past this as well. As far as I can tell the correct way to do this would be to have a LineTotal field in the table, drop a textbox on the InfoPath form for this field and set it's default value to be calculated and read-only. Then create a sum based on it.
Is this correct or am I totally missing the super-easy way to sum up a calculated field?