Coupon discount not reflected in any of the deposits

Hi I have created with another plugin a coupon code to provide discount of 15%, on the checkout page the discount shows but is not reflected on the first or second deposit.

If I complete the order the discount is applied on the second deposit, but still the customer is not able to see that on the checkout page which could mislead to think there is no discount applied.

Is there any set up I need to update? I have the pro version.

Checkout page

Order total $100
Discount (15%) $15
Deposit 1 $50
Deposito 2 $50

Order details (after purchase completed)
Order total $100
Discount (15%) $15
Deposit 1 $50
Deposit 2 $35