Check if the rate is actually coming from the app, or if it's a previously existing rate.
If you are in Live mode and you think you are getting the wrong rate from the app, verify the rate is coming from the app by using first name 'Bambri' in the shipping address at checkout.
If the rate is from the app, you will see [ASR] appear at the end of the rate title.
If you don't see [ASR] at the end of the rate then it means its not actually from the app.
Double check that the product(s) are in the group you think it is
If you are seeing rates from the app at checkout, but they aren't the rates you are expecting, then make sure the product belongs to the group that you think it is in.
Sometimes you may think or assume a product is in the group you think but it isn't.
If you are seeing the wrong rate for an order with multiple product groups, check the rates for each product group separately first.
If you have a whole bunch of product groups in an order, and aren't getting the rate you think you should be getting, its best to break your test orders down into each product group to test first and make sure each product group on its own is getting the rates you want. This way you can discover which product group's rate is off.
Make sure you don't accidentally have a mark-up on the app's carrier service within the Shopify Shipping Settings.
Go to Shopify Admin > Settings > Shipping > Manage Rates,
Then scroll down and look at your zones, find where Advanced Shipping Rules is connected as a carrier service.
Edit the Advanced Shipping Rules carrier service
Make sure the mark-up fields are set to zero.