I Think I have found a solution to the manuel change of standard cost.
If a change is made to the item, then when saving the cost update, the stock_moves get the standard_cost updated for the difference and where the stock moves are <= the date.
This should eliminate the difference from the IVR and the GL when taken Before todays date.
I will upload three files here when fixing this and please download the files and help me testing this. The files will be /inventory/includes/db/items_trans_db.inc, /reporting rep301.php and &/reporting rep308.php.
Especially Apmuthu and MarkAndrew.
Thanks in advance.
/Joe