Create and install a Shipping & Order Editing module for an Oscommerce 2.3.1 installation

We have an already working OScommerce 2.3.1 installation. I need a shipping module that will charge First item a certain amount and every extra item little more amount. Tax should be added to the shipping fee at the last stage. Both amounts should be able to be edited from admin. Three Zones within the same country (A field for Zone needs to be added to the [login to view URL] file) will have 3 different editable prices. Order Editing Module will allow all Order fields to be edited. Ex: If someone wants to change the product or if we want to edit the price after order is placed. Please note that its a OScommerce 2.3.1 installation. Ask if you have any queries. ## Deliverables [login to view URL] requirements notice: As originally posted, this project does not have complete details. Should a dispute arise and this project go into arbitration "as is", the contract's vagueness might cause it to be interpreted against you, even though you were acting in good-faith. So for your protection, if you are interested in this project, please work-out and document the requirements onsite.