Hi,
In PO, take a look at Maintenance | Tax Groups. Edit the appropriate group and select the jurisdiction for GST. This will activate the remaining fields. Make sure you have the Costing method and the GL debit account set up correctly.
Also, look in your PO Company Profile on the Runtime Variables 1 tab. How the IC most recent and second costs are updated is based on your selection in the associated dropdown.
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Regards,
Softrak Tech Support