Hi Lance.
i have recent experience with this when changing my Mustang from full to Code 404. Having only just paid $690 full Rego for 12 months I changed to 404 and had nearly $600 credit. They offered to use this money on any vehicle that was registered in my name. I also believe they offered me a credit in “cash” back onto my credit card but can’t be sure. I choose to have the credit applied to the Mustang so now I won’t pay Rego for about 5 years on that particular vehicle. cheers Alan