Magento 1.7 – How to Move Coupon Block from Cart Page to One Page Checkout

The only way to solve this problem is to either require users to create a customer account prior to using this coupon or implement custom logic to validate against billing and/or shipping information to try and accomplish the same thing. Anything else would be unreliably flakey. Checking for orders placed with the same info is already pretty flaky, complicated, but doable.

My recommendation is simply not to do this and require users to login. If you have a coupon and give the customer a message telling them they need to login or create an account to use it, they will do that to save a few bucks.

Try to rewrite below block files with following functions:

Rewrite class Mage_Checkout_Block_Onepage_Billing

    public function canShip()
    {
        return false;
    }

Rewrite class Mage_Checkout_Block_Onepage_Shipping_Method

    public function isShow()
    {
        return false;
    }

Rewrite class Mage_Checkout_Block_Onepage_Shipping

    public function isShow()
    {
          return false;
    }

I hope now issue related to progress will not occurs.