Shipping charge / Payment commission

First of all many thanks for developing such huge ecommerce application! I tried to install and use opencart and I find it simple, easy and smart to work with. I have problems only with Shipment charges and Payment commissions.

Shipment charge, the problem:
Be able to make the charge free for a Sub-Total amount greater than or always free. Now it is possible to do it but we need two modules: for example the Flat Rate module and the Free Shipping module. It works but if the Sub-Total amount is greater than the value filled in the Free Shipping module you have still the option to choose the Flat Rate. I think it should be better to have only the Free Shipping.

Solution for a general and more functional way to manage Shipping charge:
Put in all the Shipping modules the fields: "Apply or not the charge (single check box)", "Free for a Sub-Total greater than". In this way it is no more needed to have an additional module and when you choose the shipping method in the checkout process, you will have only one option with on the right the charge value or 0 if it is free.

Payment commission, the problem:
Often there is the need to apply a commission depending from the payment, to not apply the commission for Sub-Total amount greater than, and to not accept the payment type for Sub-Total greater than. The commission usually may be applied with a fixed amount, a Sub-Total percent value, or a Sub-Total percent value with a minimum amount.

Solution for a general and more functional way to manage Payment commission:
Put in all the Payment modules the fields: "Apply or not the commission (single check box)", "Per cent value commission", "Minimum Commission", "Free for a Sub-Total greater than", "Payment not available for Sub-Total value greater than".
If the "Per cent value commission" is set and the "Minimum Commission" not, it will be applied only the "Per cent value commission", if the "Per cent value commission" is not set and the "Minimum Commission" is, it will be applied only the "Minimum Commission", if both are set, it will be applied the "Per cent value commission" if it is greater than the "Minimum Commission", otherwise it will be apllied the "Minimum Commission".
If the "Payment not available for Sub-Total value greater than" will be set, the payment will not be available in the checkout process if the Sub-Total value is greater than it.
It should also be great to have the commission value on the right of the payment description in the checkout process, like it is for the shipping charge. Moreover it should also be great to have the payment commission showed in the checkout confirmation page like it is for the shipping charge.

I hope this can help to improve this fantastic application.

Payment commission, the problem:
Often there is the need to apply a commission depending from the payment,

I suppose this extension might help you to set fee for depending from the payment method.