Yes 1.0 is your device normal resolution, no mater what it is, pixmax , Vive , rift.
1.2 is 1.2x your device normal resolution (physical pixels in panel)
Etc..
Think it bit like Antialising , thats just what it is. Brute force method, render image in higher resolution than your panel and then scale it down > less jaggies.
Sent when im drunk with my iphone near me :)