kokapelli have you tried that with 147gr rounds?
I'd say they're different sizes. If you're going IWB, I'd rather have more rounds of the better caliber. If you're going for pocket carry I think you'd be better served to look at the p3at versus the 642.
I keep looking at P3ATs and P11s, and...a P11 is not as small as people try to say. Neither is the PF9.
It "might" be a pocket pistol in the same way my Kimber Ultra Carry is a pocket pistol.
That is, it will fit in my pocket, but is not as small/light/concealable as a 642, or my PM9, and is an order of magnitude larger than the P3AT.