Class E Amplifier Sim vs. Real discrepancy

I'm currently working on the design of a Class E amplifier to drive a PZT piezo transducer @ 1.5MHz. The desired output power is ~1.6W, and the Vpp across a 77Ω load in simulation is ~32Vpp. However, the same values on a PCB yield only a Vout of 13Vpp on a similar resistive load. Is this the result of component tolerance shift (Capacitors are 5%, inductor is 20%)? I have repeated this circuit on breadboard and had similar results.

I have also noticed in the literature that there is a DC power conversion factor of 0.5774 typical. So far, I've been calculating the amplifier's efficiency by Pout/Pin where Pout = Vrms^2 / Rload and Pin = Vdc x Idc. Should the factor be a part of the calculation?

Thank you,

BJ

---------- Post added at 11:39 ---------- Previous post was at 11:37 ----------

Also, I have been having a difficult time finding information on driving circuitry for the amplifier. Can a MCU drive the MOSFET directly?