Sally Wals (asker) Aug 30, 2014:

Thanks guys! All making sense now. I went ahead and asked my PM too, here's what he said, just for reference:
これはわかりづらい表現ですね。
確信は持てませんが、おそらく、下記のような意味だと思います。
XXXX社が責任をとるのは、製品の交換、修理または製品の売上の処理（売上処理をなかったことにする、または返品承諾書により、返品を受け付ける、という意味だと思います）
つまり、不良製品があったときにも、この項目に書いていないこと、例えば返金などはしませんよ、という意味だと思います。

Port City Aug 29, 2014:

Since it's under "warranty", it should be a "partial" deduction of the sales price. In business-to-business transactions, sales are usually made on credit; by the time a purchaser finds any defect, they may not have made the payment. Hence, it's a matter of accounting process to add the deduction amount. The term 製品売上処理 is usually called「売上値引」.
http://hamano-accounting.jp/info/keiri/shiwake/salesdiscount...

David Gibney Aug 29, 2014:

Maybe "full or partial refund" would convey the nuance better.