A user sets the same Discount percentage for different Products (Ex: 15%). The Order Total Discount is different (Ex: 14.99%).
On the Order Header, the following formula is used to calculate the Total Discount:
|100 - ((Net Amount / List Amount) *100)|
Mathematically, the result is 14.99%.
This is working as designed. Total Discount is rounded to two decimal places.
CRM Help Documentation: Discount Rules