In some cases, you may need 2 or more copies of an extension you purchased. For example if you want have 2 Purchase Order extensions, one for different geozones, or something like that.
I've coded my extensions using a more dynamic approach compared to the core or other 3rd party module. All variables referencing the extension are based off the filename itself. This makes it much easier to clone as you typically only need to change one line of the cloned file to make it work.
For shipping extensions
class ControllerShippingXXXXXX extends Controller {
to include a "2" in the name:
class ControllerShippingXXXXXX2 extends Controller {
$_['heading_title'] = 'Some Shipping Mod';
to include a "2" in the name:
$_['heading_title'] = 'Some Shipping Mod 2'
class ModelShippingXXXXXX extends Model {
to include a "2" in the name:
class ModelShippingXXXXXX2 extends Model {
If you want to have extensions work for different stores, you will need to use my Ext2Store module that lets you determine which extensions are active for which store