You can overcome this buy using % of order instead of fixed value.
Furthermore i would like to have the possibility to set different values (€ / %) for referrer and friend.
Also i would like to see that the coupon is activated after x number of days.
Here in the Netherlands, people have the right to return the products until 14 days after delivery. The coupon should automatically be activated only after these 14 days.
Otherwise people could buy for a large amount, get an coupon , use the coupon and than return most/all of the products