AbleCommerce Shopping Cart Software

The current checkout process for multiple destinations goes from billing address to shipping destinations to shipping methods to payment. If I wanted to add an extra step between shipping destinations and shipping methods, is that customizable or is that something that requires source code?

Thanks.

This is customizable without source code. In fact checkout process makes use of ConLib/OnePageCheckout control. All you need is to place another panel into that control and put some show/hide logic to control its display.