Why are there multiple child support calculators?

When I visit various siste to use the NC Child Support calcutor (Form “A”), I’ve noticed some include the number of nights the child is with each parent (Rosen’s) and some do not include that (the NC official site). Why are there different child support calculators?

I can’t speak to why other websites don’t include the number of overnights on their calculator but I can tell you it is a factor that the guidelines consider. Worksheet A applies if one parent has more than 243 overnights a year, Worksheet B applies if both parents have less than 243 overnights.