From experience, my daughter started coursework at NCSU when a 15 yr old high school sophmore and the colleges to which she applied did not like to see the college credit as two high school semesters. Some would not transfer a course that was used to fulfill a high school requirement. It also makes your transcript look strange and taxes their credulity if several courses were taken. The number of credits exceed what a "normal" high school can possibly fit into a four year schedule.
It was an interesting experience when we went into the admissions office at NCSU to enroll her in a couple of their courses; Latin and Biology were the first two she took. The counselor was very condenscending initially. Then we showed him her SAT - 1340 and PSAT - 222 (a National Merit Finalist); he became very cooperative. Her scores were above their average entering freshman. She finished with 41 hours and above a 3.9 GPA. (She just had to go to camp with her friends at church and missed the first four days of a summer school math class, her only B.)
Colleges and universities are going to have to educate themselves on the growing numbers of homeschoolers who will be attending in the coming years. For one thing, the 'carnegie unit' idea so often used by colleges is turned on its head in homeschooling. Most colleges assume a 'carnegie unit' to be equal to 180 hours of schooling. A study was done in the last year or two to see how much of that time was actually spent in LEARNING. The study assumed 1080 hours of schooling; equal to 6 courses in a typical high school year. From that 1080 hours, the study backed out time spent in changing classes, administrative tasks like taking attendance, picking up and returning papers, homeroom, lunch time, and even absenteeism. It was determined that only about 365 hours of that 1080 total was spent in actual direct instruction or 'learning'. That equals about 60 hours per course!!
If you compare that to the time spent in an average college course over a semester, you'll see that the time spent in a college course is very close to that spent in a high school one. Figure 3-4 hours a week in class in a typical 18 wk. semester, and you have from 54 to 72 hours spent on the college course. To my mind that DOES equal a high school credit!
Many colleges like to see community college courses on a high schooler's transcript because it gives them an idea that the student can handle college work, but also that the student has been able to do work in an actual classroom with other students.
I don't understand why the college is reluctant to allow college credit as well as high school credit for a community college course. If the student had taken an AP class in high school, that student would be given high school credit for it, and if the AP test grade were sufficient, would also be given COLLEGE credit for the course.