I would think that the technician would have noted the color loss in the report. SOme color loss might be caused by the white boxes "washing out" the red. (Both of my VEPs- 1982; 2002- used a B/W moving checkerboard pattern.)
My second VEP was stopped early because the technician said that it was overtly noted that I was showing problems.
Due to the extreme sensitivity which can be measured by the VEP, your neuro should be able to tell you if there is something impairing your nervous system.