If this is not the first fill after new plaster, then I would go ahead and raise the calcium to 200 ppm.

If it is the first fill after new plaster, then I would drop the PH to 6.8-7.0 and after a 3-4 days, test the water and if the CH is still below 200 ppm and most of the plaster dust is gone, then I would add calcium.

Plaster dust can add quite a bit of calcium to the water and it is actually good to start a new plaster pool with a low calcium level since this will dissolve much of the plaster dust and save a bit of time vacuuming it out. Dissolving the pool surface due to low calcium levels is a very slow process so I would not worry too much the first week. But after that, if it is still < 200 ppm, then I would go ahead and add calcium.