I understand now. Thank you Gang!
Last question - Say you have a mixed block-event design and the contrast is [1 -1]. For an individual subjects, are the parameter estimates for the difference (A-B) actually %signal change regardless of the scaling as long as its the same for the two conditions (dmBLOCK(0) or dmBLOCK(-X))? Of course, to be able to take this to group level, it would be necessary to have the same scaling factor across subjects right?