Is the One-sided Spectrum from Spectrum Scope scaled ?

I have computed the power spectral density in a MATLAB function block in parallel with the SIMULINK Spectrum Scope. For both I took the single sided spectrum. However, the amplitude values from the Spectrum Scope are almost half my results from the code. So, for the Spectrum type in the Spectrum Scope if you choose:

 One-sided ([0...Fs/2])

Is this single sided spectrum scaled ?