Child support after 18

I was searching your questions regarding this and I found 1 post. The answer given was that child support does not continue past 18, even for a child with a disability; however, on your website under “Everything you need to know about child support”, it states that it does continue if the adult child is physically or mentally incapable of self support. There seems to be inconsistences on this topic, could you help clear this up?
Thank you

With some exceptions, a child support obligation typically terminates once the child is 18 years-old and has graduated from high school.

But in no event does child support continue past age 20. North Carolina does not have a specific statute regarding child support for children with a disability that are over the age of majority.