You're not comparing two similar expeditions.

We can show you the numbers, but we'd be doing you a disservice if we didn't say this first: Kang Yatse 1 Peak Expedition and Mentok Kangri II Peak Expedition are not alternatives — they are different sports. One is a 15-day summit expedition reaching 20,997ft, the other is a 12-day summit expedition reaching 20,505ft. If you're choosing between these two, one of them likely isn't an option for you yet.