Glad it worked out for you.
I don't recall prorated warranties back in the day when I did sealed system work.
What I do recall is if the sealed system was under warranty (1, 5,10 years) it got repaired free of charge.
There was no paying money back to the customer for warranty that had not been used.
Seem when the warranty is prorated the customer is simply selling what warranty is left on it back to the manufacture.
Why do that? It's under warranty, just fix it.