This is on the basis of a recommendation from the FORS instrument scientist, Ray Stathakis. The last time FORS was scheduled for a full-night proposal was May 1997. FORS has been used in service mode for the equivalent of less than 1 night per year since that time. CCD is more than twice as efficient as FORS over the whole range.
Most failures are due to cables, controllers and other peripherals.
In addition, the use of an extra CCD involves excess work for the staff and more stops to fill the liquid nitrogen.