Cashback excluding taxes

Our product price including tax is 15,500 and the cash back showing on product page and shop page is 620.00 (with 4% cashback), but in the cart its showing as “cashback of ? 525 will be credited to your wallet”, means the amount after deducting tax is taken for the cashback calculation. I want to show the same calculation (cashback on the amount deducting the tax) on the shop page as well, means 525 on the product & shop pages instead of 620 as shown currently.

Also, how do I apply different cashack % for a sub-category? when I updated the sub-category with a different %, it’s using the parent category for the calculation.

The page I need help with: [log in to see the link]