This is a good idea and would also solve the issue described in the forum years ago: https://whmcs.community/topic/291811-enforcing-domain-recurring-amount/

The gist is that a manually placed new renewal order will change the renewal price to live rates rather than pull from that specific domain's set recurring amount in WHMCS.

By generating an invoice rather than creating a new order, presumably this will be done like how all other products renew: by referencing the products own direct pricing.