Haven't tested that yet but would imagine so... Or it may be the opposite.

If a Multipool were to jump into CGA it would raise the difficulty, which would make CGA's more elusive, which would make worth more, but does that make it more profitable? Maybe not when the difficulty is still high but once the multipool leaves CGA for awhile CGA will become more profitable as the difficulty lowers and the price would(should) stay the same until the difficulty rises again.