I just don't see the point. A chain is cheap...and you should use cheap chains because they aren't any better than the more expensive ones. A Sram PC1110 costs around $14. Same for a 9 speed chain. Let's do a little bit of cost benefit analysis on getting 15,000 miles out of a $14 chain using your method.

Based on your maintenance schedule, you've taken your chain apart about 18 times. If it take 15 minutes to do the cleaning, that's about 5 hours of your time. I suspect that it takes more than 15 minutes because you are using water based solvents in the ultrasonicator...at least I hope you are! You need to get rid of the water so there's a lot of flushing and chasing. You also have to clean the rest of the drivetrain so your cleaning task is likely closer to an hour. That's 18 hours of messing with the chain (and 18 times of breaking and making the chain). Your time is worth something so let's figure $5/hour. You've spent $90 of your time on a $14 item. Is it really worth it?

Using my method, I've used 4 chains over the same mileage. I've spent $60 on my chains and about 15 minutes per chain (about an hour total) in cleaning the chain and installing it. I also don't have to spend an inordinate amount of time cleaning my drivetrain because my lubricant is cleaner. Instead of cleaning my bike, I'm out riding it.