LTSpice AC analysis and DC analysis don't agree?
When in doubt, if a transient simulation isn't giving expected results, decrease the maximum time step.
I was able to reproduce your results with the default settings.
But when I set the maximum time step to 0.1 us, I get much closer to the expected results:

(n002 is the voltage source output terminal)
When I reduce the maximum timestep to 0.02 us I get very close to the theoretical amplitude: