View Cart Page Modification

Say you are selling product that costs 1000$ and offer 50% discount for it. Now in view cart page I see

Subtotal 500$

Discount -500$

Total 500$

1. Is this the proper way to show it? Can subtotal be presented without discount being applied?

Also when promotion is applied to product, in view cart page next to product name, there is a Discount button. When you click it popup explains calculations.

2. Can these calculations be not a popup but seen in "balloon" instead of discount button and not via popup ?

First question: that's because you give a discount on the product, not the total order. Confusing yes, but not really incorrect.

2. I'm not sure what you mean.