Free shipping after discount coupon

Hi,

Feature request or coding help.

Is it possible to add a setting to disable Free Shipping until after a discount coupon has been applied?
For example, customer adds items to cart, without a subtotal above the amount for free shipping. Then they use a coupon code to bring the final subtotal below the amount for free shipping. But right now they still get free shipping, because your plugin is only checking subtotal before coupons.

If there was a setting, such as there is in the standard Free shipping option in woocommerce, to apply after coupons?
Or some code to add to functions to subtract coupon value from subtotal before deciding if free shipping should be given?

Thanks,
E