Show fields only when a refund has occurred

Good afternoon, first of all thank you for the usefulness of this plugin which is very useful.

I have a doubt that I would like to solve:

I have added some billing fields which are related to order refunds, which are as follows:

order_total_fax_refunded
order_total_tax_minus_refund
order_refund
order_total_inc_refund

I would like to know if there is a hook or an option to add the condition that these fields only have a value when there has been a refund in the order, otherwise they are empty.

Thank you. 🙂