ReadyToShip itself does not show live rates in Shopify checkout.
However, we recommend an excellent Shopify app to do this.
This app allows you to quote rates to customers using your own account rates from a large range of Australian carriers or use Australia Post's standard rates.
There are also lots of business rules you can use, and a product editing tool to add dimensions to your items in Shopify for more accurate pricing.
Click here to install it, or learn more: