Is that corrected to set the LineDisplacement ux,start,ref= 0.5m at the bottom boundary in Plaxis 2D seismic analysis?

Hi all,

As explained in, the amplitude of the motion is double when body wave reaches a free surface due to impossibility of transmitting stresses and therefore ux,start,ref= 0.5m to account for that. However, it's still a question when the result shows peak acceleration is about half and one time of input signal at the bottom and the surface, respectively. In Plaxis version 2011 the displacement is only set as 0.01 to convert cm to m for input SMC file. Something is still not clear for me to understand the above explanation and to decide the input in our project case. Would anybody explain me more clearly?

Thank you!