To expand on what R_Kelly is saying, if you've processed the image before in an older version of Camera Raw, it remembers that you have done so and faithfully reproduces almost all of the settings, with the idea that you'd like to start with what you did before.
Personally I think it's a bit silly, since PV2012 actually does a better job of the conversion, as well as the fact that not everything is reproduced (look in the area of color fringing, for example).
If you want to start over with the PV2012 process, just click the fly-out menu icon and choose Camera Raw Defaults.
Alternatively, you could clear your entire cache of stored settings.
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