# What is the link between conjugate matching efficiency and amplifier efficiency?

In the design of a class AB amplifier, there is part of the understanding that I miss. It is well-known that the maximum power transfer is achieved when the load impedance is the complex conjugate of the source impedance, $$Z_L=Z^*_S.$$

It is also shown in many textbooks that using the conjugate match, the maximum attainable power efficiency is 50% (and also on Wikipedia).

I am well aware that the conjugate matching is not a good choice for large-signal amplifier design, however, if I was to load my amplifier with the conjugate match, does the maximum power theorem imply that I will only be able to get 50% efficiency out of my amplifier, no matter the biasing?

In simulations, I tried loading my class AB amplifier with the conjugate of the small-signal output impedance, and I achieved a drain efficiency of 55%, with the amplifier driven pretty heavily into saturation.

How is this possible?