Percy raised an eyebrow, not really sure how to react to Sirius' clear habit of random moodswings. Percival was never very good with people, after all, and had a hard time figuring them out on first meeting.
"Percival - right. Or Percy," he said, turning to look around at the amass of things around him. There was quite a lot of it, and he had the sudden urge to try and put it all into a better order.
"Owe--? Oh. Nothing. Don't worry about it." It wasn't like he hadn't gotten it for free anyway.