Here is the field description for the "unit cost" field:
Numeric (Real) - Unit cost for the line of distribution; it gets ignored for negative inventory adjustments, but gets used for positive inventory adjustments. (Note: If this field is not included during import, it is calculated for you based on Quantity and Amount values.)
Here is the field description for the "amount" field:
Numeric (Real) – Amount for the line of distribution calculated during the import process. A positive amount denotes a debit, while a negative amount denotes a credit. This field is used for exporting only.
Here is the reality:
The unit cost field is not used by Sage when doing inventory adjustment imports. If you use this field doing a import, the result will be that all of the negative inventory adjustments will have a negative value and quantity impact and all of the positive inventory adjustments will have no value while impacting the quantity. This means you have an inventory adjustment with only debits (expense) to the P&L. In order to properly do imports that have the desired financial impact, you need to use the amount field to value the overall transaction even though the instructions say the field is for export only. Sage will calculate the unit cost for the transaction. However, the "amount" field for quantity increases needs to be negative and not positive. The positive amount being a debit means a debit to the P&L and not to inventory as you would expect, and a credit means a credit to the P&L and not to inventory. So you will have a positive quantity adjustment and a negative in the "amount" field. The instructions are misleading at best and backwards at worst.
I have brought this up to Sage several times and they do not seem concerned about correcting their documentation.