***Note: this is purely speculation.***
The purpose of the lag offset (to my understanding) is to sync the video with the audio. (Usually) The only reason this is necessary is due to the large amount of circuitry the image/sound have to travel through in HDTVs (or some bullshit like that).
As for the LCD vs plasma question, I suggest trying any possibly matching settings and seeing which one works best.
And if you think its a calibration problem, you can always set it to HD and make your own offset anyways. If there is no problem, when you set it, the number will be zero. If there is a problem, the game sets the lag for you. It's win/win imo.
Setting the type of TV only matter in lag offset detection/setting iirc. It has no effect on gameplay (other than lag obv.), graphics, or any other aspect.
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[quote:e0e72f52e0="J.T."]One week, only 7 people had Awesomeness Detection on, and they were all young and did not play well. Thus, Naked Brothers became DLC.