I have not seen this suggested yet.
The thing is add an option to give a refund to a buyer on his order. Like “thank you for previously organizing your order so I can work more easily on it, to thank you I am giving you a $X discount”.
This would be a strategy in some cases to make a customer come back and be loyal to you.
And also to show them you appreciate the fact they ask for LESS and not for more, as people usually do.
So, the idea is really that, like offering more extra gigs once the order is made, offering a discount once the order is made.