It is very important to know for all of us that why and when the standard cost of an item changes. FA tries to keep the weighted average of the material cost so that the Inventory Valuation reflecting in Trial Balance shall be same as that of in the Inventory Valuation Report.
FA does this by calling update_average_material_cost function from 5 different places in FA.
1. When a Stock Movement is Voided. Even if Location Transfer is Voided. (As per my understanding on Location Transfer Void this function shall not be called because Location Transfer doesn't affect the overall cost of the Item in FA)
2. When Stock Adjustment is Done either positive or negative if the Cost of Adjustment is manually changed to differ from the existing standard cost.
3. When the GRN of Item is recorded.
4. When a Purchased Item is Returned to Supplier
5. When the Direct Supplier Invoice is Recorded.
You can search the said function in FA to find out its location.
You can create a New instance of FA and do random operations to find out the change in Standard Cost and Log it to find out the behaviour of FA.
Q#3: You can do manual feeding of Standard Cost if you totally disable the call of this function in FA.
please go through this post http://frontaccounting.com/punbb/viewtopic.php?id=8157
You can also go through this post http://frontaccounting.com/punbb/viewtopic.php?id=8184
You can go through this post http://frontaccounting.com/punbb/viewtopic.php?id=8238
These problems were discussed in detail earlier.
We are hoping that in FA 2.5 these problems will be handled properly.