Hi,
Sorry for that your message had slipped.
You still didn't answer me though.
Did you try to change the value of the "apply discount" option ?
The system of taxes and discounts calculation is quite complex but I think that it might do what you want.
If not, can you please give a complete example. Ie, the price of the products in the cart, with and without taxes, the tax rate, the points used, the result that you have and the result that you would need to have so that we can try to reproduce the problem on our end ?