The current logic requires a return order/refund to connect the refund to an article on the original order, and for those refunds, only the full article amount can be refunded.
This is limiting since it is not possible to:
Refund a fee, such as refunding or adjusting charged shipping
Partially refund an article
Refund an article that is not actually sent back
Allowing refunds by amount only, and making the article row and quantity optional, would make the return logic more flexible.