MYOB Accounting Plus uses the Weighted Average stock valuation method
That is, the total value of a particular item is divided by the number of units on hand to determine the value (cost) of each unit. For example, if you have 100 units of item Item01 and their total value is £1,000, the cost of each item is £10. (1,0000 / 100 = 10)
This valuation method is fixed and cannot be changed in MYOB Accounting Plus.