Hello
my friends I have a problem concerning the validation of Credit Memos finaciére I want when validate the system have the value the cost of the item or changes the correction of the cost of the item
Not exactly sure what you are asking but if you asking about reversing out the same cost as the original sale then you should take a look at Exact Cost Reversing. See the following for more details...
Answers
https://msdn.microsoft.com/en-us/library/hh168565.aspx