Right, no Thirty-Double-Yew. No 30W, just 30. But a warning about Thirty-Weight: There's a cheap Non-Detergent version that shouldn't be used in a gas engine unless specifically recommended. In other words, don't use "30ND." For almost every application, use "30HD" for High Detergent.
Thinking back to the Oil Consumption - OP's question... Back to the Breather Box, I wonder if it got flooded with oil from being too full and just can't clear it out, so it works like it's clogged, which will in turn allow oil to be blown out.
I looked at that Owner Manual and it was very clear that the Cap/Dipstick IS to be screwed back in to get the oil level shown correctly. Measuring with the bottom of the Cap against the Top of the Oil Filler will lead to an overfill.
Related to KY oil level: A couple years ago we had a rash of engine failures on those, and it was related to low oil levels. Hate to say, but 4KY is a bargain basement approach to a generator: Air Cooled, Splash Lubed, 3600 RPM. It's going, by nature, to use more oil than a cooler, better lubed, slower running engine. They still last a LONG time, but they are a maintenance item to keep in mind.
