I wouldn't say more, rather a stable level. As it grow it will consume more Ca. You might have to test evryother day and see how much your tank is consuming. If you have lots coraline, they consume Ca too. Hth
Depends on how much of an increase in animals and how you are adding the Ca2. Simple logic may apply here, the more there are to eat the more you need to add food.
Yes it is true the more sps you have the more calcium they will consumed as they grow.You will have to add calcium via doser or other types like Calcium reactor to keep up with the demand to stay at the desired Calcium level your tank at.Stable is key in reef tank .