Our Square platform uses automatic calculation to get to the final shipping price when you choose POSLAJU as your default shipping method in your store setting under the "Configuration" tab.
This calculation is based on the store location setting that you choose (ie: Selangor), customer address location (ie:Sarawak) and the product weight that you entered in the "Add New Product" section.
The shipping rates used are based on the current officially published POSLAJU rates + handling fees + fuel surcharges (10% + 15%) + GST (6%). The price is then rounded to the nearest cents. This is the same shipping rate being used by all POSLAJU center and Mailboxes Kiosks.
So, keep in mind, it's important to key in the best estimates of your product weight since it will affect the shipping rates.
Happy selling! :)