SS v2 very simply consists of a duplicate angle value for response types 7 and 5 stored in c4eva's C/R replay table and was added in iXtreme v1.6. Older 0800 ripping firmwares and Kreon's firmware will record the angle just once, which results in SS v1.

The problem is that Kreon's firmware does not do an actual measurement to get the angle, but simply uses preset angles that all games currently use and applies a small jitter to them. Storing the angle twice allows us to be fairly certain that this is a real angle measurement made by an actual Xbox 360 drive. If a game was intentionally or accidentally mastered with one or more angles that deviated far from their CCRT targets, it would need to be ripped with a drive that does actual angle measurements in order to mimic the original disc's responses.

If that drive also supports SS v2 and you have the default option enabled to "Trust SS v2 angles", abgx360 will accept them instead of complaining about deviation from the (obviously incorrect) CCRT target. It will still check and alert you when appropriate about the v1 angle deviation from the v2 angle, which should be zero unless the v1 angle has been adjusted to its CCRT target by an older version of abgx360, or if a 359 degree v1 angle was adjusted to 0 for compatibility with iXtreme < v1.4.

If you have decided not to trust SS v2 angles by unchecking that option, abgx360 will compare both the v1 and v2 angle to the CCRT target as if each was a v1 angle and alert you when appropriate; this is useful if you're paranoid and think someone has maliciously tampered with the angles.

Note, however, that abgx360 v1.0.2 or later will never fix angle deviation or C/R data for an SS v2 without a verified ini and SS file (although it will still adjust any 359 degree v1 angles if you have that option enabled). If your SS v2 is fucked up, something is seriously wrong and you need to rip again or use the SS provided by AutoFix, as there is no reliable way to fix an SS v2 using decrypted CCRT data.