Grading services often require homeschool teachers to save and mail student work to the organization. This record-keeping can be burdensome, and is not particularly necessary.
In addition, there is a danger in delegating the grading to someone outside the homeschool. When the homeschooling parent grades the child's daily work, he is immediately aware of both weak and strong spots in his child's performance. Based on that knowledge, practice can immediately be assigned to address weak areas, or eliminate unnecessary 'busy' work in those subjects that the child has already mastered. While waiting for a grading service to return the grades, the child continues to falter in weak areas, or suffer boredom from undue assignments in areas mastered. Turning the task of grading over to someone else robs the parent of the immediate feedback that genders the 'perfect fit' for your own program.
Further, because the homeschooling parent is already acutely aware of the student's performance, many homeschool families don't keep grades at all. However, for those who desire a permanent record of work, CHC suggests creating a portfolio of 'best work' for each school year, and the use of CHC report cards.