Referral by product quantity

Hi Kento,
I am very frustrated with the setup of Affiliates Pro for getting it to allocate referral amounts to an affiliate based on a fixed amount and by the number of products in the customer’s shopping cart. Therefore please let me explain again what I am trying to do.
Every affiliates is assigned a unique coupon code. Example coupon code ‘xy’ for affiliate ‘John’. This coupon code covers only certain items available through the website. Example item ‘A’.
When a customer places an order for:
1) One number of item A and enters coupon code xy, customers gets a fixed discount and automatically John gets a fixed amount. For example $1 to each. This is working fine.
2) Two number of item A and enters coupon code xy, customer gets a fixed discount = 2x $1 = $2. But John only gets $1. I want John to get $2 too. This is not working.
3) Two number of item A and some other items (not covered by coupon xy) and enters coupon code xy, customer gets a fixed discount = 2x $1 = $2. But John only gets $1. I want John to get $2 too. This is not working.
Could you please find a solution to resolve cases 2 and 3. Please be detailed in your reply with regards to parameters setup in Affiliate Pro.
Regards,
Vijay