The introduction

Here is example of adding subtotal rows to grid, based on demo tables SPFLI / SFLIGHT. 

Suppose we have table with 7 columns (flights info per dates), which contains subtotals by flight arrivals & departures. Herewith, subtotals by CAPASITY column will be calculated in ABAP printing program and passed into Excel form as values. But subtotals by OCUPIED column will be passed into Excel form as formulas :