Spray converters get a bad rap because most guys slap them on flaky scale rust and call it done, which never works. That black coating you saw is just iron tannate, and it only holds up if you knock off the loose stuff and let the product soak into solid metal. Real rot with deep pitting will still come back from behind, so keep an eye on those frame spots in a year or two.

The clock thing is the part that gets me, because if his stove and microwave both jumped ahead by 48 minutes that means they lost power long enough to reset and then picked up a wrong signal from somewhere. Smart meters are supposed to send time syncs to the grid, so if yours and his are pulling from different nodes you'd see exactly this kind of drift after a storm knocks things loose. Next outage try comparing the timestamps on your meter's last power loss event with his, because that gap will tell you if it's a real data problem or just clocks resetting at different times.