WTF are you talking about? 240 deg of articulation? Do you have any idea what you are saying? DO you know anything about how a Class A/B amp works? Nevermind, stupid question. The above statement prooves that the answer to that is "no."
You've only got half, literally, of the equation. A Class A/B amp works in a push/pull configuration. Each half of the push/pull pair is on for more than half the wave form. Around the 0V point, both sides of the pair are on giving overlap (and wasting power) A Class A has a single drive device that produces the entire waveform itself. A Class B has a push/pull pair that divides the waveform perfectly in half. The lack of overlap and the fact that each device is off half the time means that it is more efficient than a Class A or A/B, but since the devices have to "hand off" the waveform at the 0V point, the slightest mismatch equates nasty distortion. This is the main reason that Class B amps aren't used in car audio. A Class D amp uses a series of cascaded high speed switching devices in the output stage. Ecah device is only ever fully on or fully off. Because there is never a half power situation with the output devices, there is minimal waste in the output stage. Depending on the degree of overlap on the Class A/B, it can be up to 75% efficient (though finding one this efficient is rare) but it is most efficient at full power. A Class D could theoretically be 100% efficient, in fact the output stage is generally around 95% efficient, but the major source of losses, and heat, is the power supply in a Class D. A really efficient power supply is usually around 85% efficient thus limiting the overall efficiency potential of the amp. Because the output devices are only ever fully on or fully off, a Class D doesn't get less efficient at partial power.
The part that you are fully missing is that every type of linear (or semi linear like a Class D) amp reproduces the entire waveform. If it doesn't then it is broken and would produce a ton of distortion.
