We take your coupon offline when the budget is 80% utilized, and we allocate the remaining 20% to cover for possible redemptions from customers who have already clipped the coupon. For customers to have the best experience with the coupons, we allow them to redeem coupons for a window of approximately 30 minutes after we disable the discovery of a coupon.
If 20% of your budget does not cover the customer redemptions in the 30-minute window, then you might see the spend exceed your budget. The risk of the spend overshooting your budget decreases for higher budget amounts. Budget over-spending occurs during high traffic events and when your coupon is combined with other promotions, such as lightning deals.