When you create a coupon today, we can't asociate this coupon to a specific Zoho Books account, in the same fashion as we can do it for Plans and Add-ons: it all goes to the generic "70960000" discount account and we don't know what amount of discount we have given for each Product...
To improve revenue management and profitability, it is key to know how much discounts we have made for each Product!
The SIMPLE SOLUTION to this issue is to let us choose a specific Zoho Books account for coupons, in the same way that we can choose it for Plans and Add-ons !