Would really like to move to AbanteCart, but  need to configure shipping rates by the total price of an order on items having the "Requires Shipping" option turned on.  Several shopping cart software companies offer this as a core feature or as a module/extension.  It seems that the newest method is to have a base range such as $1.00 to $25.00 at X amount; then increments added as plus{+) percentages to the base rate as in $25.01-$50.00 = +10% and so on.

Is there any possibility of adding this feature?  I'm happy to pay.