Description
This article gives an overview how WMS calculates landed Price/ last Cost.
Detail Steps
Case Scenario
Company ABC has Item #RAW-001
In Accounting software Item shows below details:

In WMS Item shows below deatils:

Why WMS and MYOB shows different Last Cost?
The buying code on the item is GST.
WMS don't know if the Last Purchase really was GST or not so system assume the tax code on the item was used.
WMS use the price less 10% tax (1.067014/1.1=0.9700127272)
Solution
Update the items to N-T if you don't usually pay tax on those items.
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