This promotion is configured in such a way that if you redeem multiple discounted items within the one sale, and the coupon’s value is worth more than the total of those discounted items, they will all be discounted only up to the value of those items.
Go to File > Sales > Promotions > Coupons > Add > Discount Type: $ Discount off Total > Select: Multiple Redemptions per Sale.
When coupons are redeemed for up to $60, only $45 worth of the coupons are within in the sale, so that is all that gets discounted.
The remaining value on the coupon if not spent is not re-issued or redeemable in another sale.