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: Bhagirathi I Peak Expedition and Bhagirathi III Peak Expedition are not alternatives — they are different sports. One is a 18-day summit expedition reaching 22,493ft, the other is a 16-day summit expedition reaching 21,175ft. If you're choosing between these two, one of them likely isn't an option for you yet.