KCD_EXCEL_OLE_TO_INT_CONVERT even takes care of blank cells and is available in older versions of SAP.
* Add values to internal table
SORT t_cells BY row col.
LOOP AT t_cells INTO wa_cells.
MOVE : wa_cells-col TO l_index.
ASSIGN COMPONENT l_index OF STRUCTURE itab TO ..f_value...
MOVE : wa_cells-value TO ..f_value..
AT END OF row.
APPEND itab
CLEAR itab.
ENDAT.
ENDLOOP.