Adjustment means to remove the effect of all the other columns not in the contrast. In gPPI, the omnibus contrast does not include any of the covariates (e.g. movement and other noise). The adjustment then removes them from the BOLD signal. The reason for the adjustment is that you are trying to isolate the neural of the BOLD signal.
In the second-level, you are wanting to extract the data to make your own plot outside of SPM. Thus, you want the data as input into SPM, you don't want the adjusted signal.
Hope this helps.