I may recommend a very essential and comprehensive article by Leslie Vail, you will have a very thorough understanding of the "Transaction Flow" among SOP tables (Work, Open and History) on the link below;
Table Names and Transaction Flow
The main essence that you may consider is to distinguish among the various documents status to be categorized in your reports. Regardless of when the posting occurs (in your case, mid of the day), I do believe that the sales (document date) is the date that you should filter on.