Both full refunds, and partial refunds are taken care of by the plugin.
When an order is refunded, it will update the commission earned for that order, and also deduct it from the “unpaid commission” if it has been granted already (and not yet been paid out).
For partial refunds it will recalculate and only deduct commission for the amount that was refunded.
You can also use the “Delay Commission” option under “Payouts” to delay awarding them the unpaid commission for a certain amount of days, for example the length of your refund policy:
