S 18's HS offering college credit for HS classes: worth it?

I have three children who went to rigorous private high schools offering both AP and dual credit courses. All three kids took maximum advantage of dual credit classes and graduated with between 24 and 30 credit hours. All three went to well-regarded, but not super elite, private universities. Thanks to these credits:
Child #1 graduated in four years with a double major, including a semester of student teaching and a change in major).
Child #2 graduated in 3.5 years (including more than one change in major) and transitioned immediately into a master’s program, finishing both degrees in 4.5 years.
Child #3 will graduate next year after 3 years, and will head directly into a master’s program.

Dual credit classes saved us at least $50,000 in college tuition. If you choose classes and colleges wisely, the return on investment is excellent.