Hello John and thank you for waiting the required time to analyze the case and figure out more about your request.
We have the feature Force Chronology for Sales Ledger Invoice in Module: Sales Ledger> Settings: Account Usage S/L which disallow to assign a newer record number to previously dated documents.
Please refer to the section: "Force Chronology for Invoice"
http://www.hansamanuals.com/main/mailnumber___58981/theconf___514/manuals/version___80/swedish/hwconvindex.htm?shortcode=HW0201SETTINGS_Account_Usage_SL_Card_1_Check_Boxes

unfortunately, the code Tools>>StockTools4.hal you asked to check if can be applied to POS Invoice was not meant to be used with POS Invoice. That code updates stock and POS module doesn't work with stock.

As a matter of fact, you proposed a very good wish.

Please make this wish according to our routine and your local HansaWorld Country Manager and I will follow up with it.

Kind regards,
Giuseppe
HansaWorld