It doesn't work that way with their salt mix...each of the A & B bottles have additional elements in them aside from Ca & Alk.
If you want to add additional Ca to your tank, you are far better served purchasing a bottle of Ca to add after you have done your water change/s and know what your levels actually are, and then you can adjust them by dosing.
Not sure about the calcium part
But part A is their alk and esv tends to run a little high in alk and I always tweaked the part A used a little less tested to make sure has the level I want..
Never had any issues