All I know is, I was happy with the way Mail worked in 10.8 and now I'm not. Hopefully this update will fix things. I haven't had any issues with Mail on iOS7 on my iPad 2.
(gmail is my primary email account)
To use a simplified example...If Apple makes $5, and Samsung makes $5, and the other companies collectively lose $2, then total industry profits are $8 (5+5-2). Apple obviously has a 5/8 share of the profits (or 62.5%) and Samsung has the same. It's perfectly valid. What other alternative calculation do you think there would be?