No, you can edit the date. But if you backdate the report to Feb 28, then your inventory history must be complete between Feb 28 and today, otherwise the calculated amounts will be wrong. All processes that write to IC History, including Day End in OE, must be done.
As Doug mentioned, we released a hot fix recently to address a specific scenario when printing the Item Valuation report with a date different than today. It may help, and you should contact your Adagio consultant for more information.
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Regards,
Softrak Tech Support