The method is following the existing in Opencart weight based shipping method logic but instead with the cart weight deals with the cart total amount to apply the desired shipping rate.
NEW in v. 1.1: Option to set a limit to automaticaly disable that geozone shipping if Cart Total reaches the target amount.
Multiple geo zones are supported as well - the extension could be set with different shipping rates for as many geo zones as needed.
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500:10,100:12,0:15 - Customers with orders above 500 would pay 10, those with orders above 100 but less then 500 would pay 12, and those whose orders are bellow 100 would pay 15.
100.00:0,20:5.00 - If an order is above 100 the shipping with be free, and if bellow it would be 5, but if bellow 20 the shipping method is inactive.