have a file containing invoices segregated by "A" for Active and "C" for Complete.

You could simply create another layout as a columnar list/report, select a Report with Grouped Data and click the Include Subtotals box. Add the fields to the report that you want to display and then select the Invoice Type in the Organize Records by Category screen. This will break the report down by invoice type. Follow the rest of the prompts and eventually you will be asked to add a subtotal field to the report. Select or create a field that subtotals the invoice amount from the Summary Fields dropdown and then select the Invoice Type in the Category to Summarize By dropdown. Select the subtotal placement you want and then click the Add Subtotal button.

You should save the report as a script when prompted so that you can simply click a button on the main screen to run the repotr script. Add a button to the report that reverts you back to whatever layout you wish to return to and you are done.

The Mad Jammer

And Then...there was nothing