Why is the shipping quote update called on every time a radio button is selected on checkout page?

I have a freight module that makes a request for rates that takes about 10 seconds to perform. This works well except for a delay that is caused every time I click a radio button on the checkout page. It appears that UC is re-calling the freight module's request each time I click on "My billing information is the same..." or when I change between shipping options.

UC 2 didn't do this and there is no need to recalculate the shipping rates unless the shipping information changes.

Is there a way to prevent UC from recalculating the shipping on each radio button change?