Mavericks & MBP retina resolution change

Hello

I did a search before writing this, and since I found no posts, I am posting this.

I upgraded my 2012 retina MBP to Mavericks as soon as it came available.

No problems at all installing.

But I just noticed this:

on system information, I read under display:

Built-in Retina Display 3840 x 2400.

As long as I remember before the upgrade of OS X, I used to read 2880 x 1800...

(I set the display to "more space" under System preferences)

So, is it only me?

I went to check Apple's site of MBP retina (2013's) and it also reads : 2880 x 1800 native resolution...