Why is there no Australia Post 1kg parcel post satchel option when listing an item for sale?

[whitelinens]

There is a 500g. Then there is a 3kg option (huge jump! ) Then a 5kg.

Is there a reason for this particular postage not being an option when listing?

Thanks in advance for any replies.

[porcelain_dolls_by_me]

Open a MyPost business account and then you can get volume discounts and also print 1kg labels.

It's a great service