FCC's allowable margin of error
What discrepancy? Nothing they show in the table and then in the graph is is in disagreement.  The table is of maximum allowable spectral power densities at each center frequency.  That means that for a given center frequency (in this case, 2402MHz), the power spectral density cannot exceed 8 dBm per 3kHz bandwidth.  The spectrum analyzer is set to show the power FFT with a 3kHz resolution (you can see this in the lower left corner).  So the graph is of the power density per 3kHz, and the graph is centered on 2402MHz.  There no issue at all.  No where is the power spectrum even close to the limit - 8dBm.  So it passes.  The entire span of the channel is shown, and the span of that channel meets all the criteria.  Which is that no part of the signal's spectrum exceed 8dBm per 3kHz.  There is no discrepancy to allow or not allow.  

The marker is irrelevant.  Most spectrum analyzers place a marker on the peak power measured.  Which is what we want.  The peak power density over any 3kHz bandwidth slice along the 2402MHz spectrum is -19.621dBm/3kHz.  The frequency that the peak happens to be is completely irrelevant to what is being measured, and what is being evaluated, and beyond that, almost certainly doesn't mean anything at all.  It's just a random bandwidth slice along the spectrum that happened to be slightly higher than the others.