When you add new columns to the cart object, you need to modify any any add to cart buttons that you have already added to your pages to regenerate the code for the new columns.
Instead of adding the form elements to your page manually, let eCart add the form elements for you by selecting the cart column in the add to cart button wizard and selecting the Updateable from Text box option, this way you do not have to do any binding to the element, it will be done automatically.
to add your flat rate shipping, add a new rule on the shipping tab.
Set the trigger to Total number of Unique items > 0
set the calculation to a flat rate of 9.95