Yes.

Postage calculator is showing higher amount than I want and when I went to change the discount it doesn't matter what discount rate I select -the postage amount in the listings stays unchanged.

What shows in our Site preferences page is not the same as it says in http://pages.ebay.com.au/help/pay/shipping-discounts.html#discounts. under section "

Offering discounts through the postage calculator

If you include the postage calculator in your listings, you can specify a discount that will be applied to the rates that are used to calculate postage costs to buyers. Changes to this preference will be applied immediately to your current listings."

Jeff