Yes it seemed too good to be true, the 2:1 ratio in the peak heights in the original attachment was a dead give away that something went wrong with resampling.
The other issue is that the Gamma Velorum spectrum sticks out like a sore thumb, in fact the major emission line reached the saturation limit of the CCD.
I might try this again at much shorter exposures where a lower SNR might lead to a greater differentiation between the combining techniques.
Steven