Incorrect shipping prices

I have the eshop_austpost shipping plugin selected.
As the EShop caculated price didn't look right to me I compared the pricing show in the Cart to the Australian Post - postage calculator

1. EShop is under calculating the shipping price

example dimensions L19cm x W 22cm x H 11cm
example weight 1.15kg

auspost.com.au/apps/postage-calculator.html#fast

STANDARD POST
Australia Post is showing two options for
Parcel Post (your own packing) $10.05
Parcel Post Medium Satchel $13.40
EShop displays one option for STANDARD POST $8.20

EXPRESS POST
Express Post (your own packing) $13.90
Express Post Medium Satchel $14.80
EShop displays one option for EXPRESS POST $11.22

2. When I added 4 items to the shopping cart the shipping price stayed the same.

3. Australia Post also offers the ability to have the customer sign for the parcel and also insurance.

Can you please advise what I need to change to correct these issues.

I have attached image of sample EShop cart pricing and AusPost calculator pricing