Since you are worried about calcium at this point, I would skip the "fancy scratch" and just use layer feed for a while to see if it helps.
The scratch is not going to have as much calcium as layer feed, and probably has less protein as well. Chickens are more likely to waste feed by throwing it around, if they have a mixture and are trying to dig for their favorite pieces. All of those are reasons to not add scratch it when you are trying to fix a problem with laying hens. Depending on how "fancy" it is, the scratch may even cost more than the layer feed, which would be another point against it.