Dear Omar:
In these links you can find more info about these info-structure
https://help.sap.com/saphelp_erp2004/helpdata/en/c1/3759de449a11d188fe0000e8322f96/content.htm
Sales Summary - Sales (SD-SLS) - SAP Library
http://help.sap.com/printdocu/core/print46c/en/data/pdf/lolis/lolis.pdf
Please check it
Regards Jose Antonio