Please extend the ability to set the child-adult equivalency factor past age 19. They might not be "kids" when they're 20, but they might still be dependent, at least partially. Not being able to adjust their relative cost as it changes limits accuracy. It affects me, in particular, as my kids go to college and much of their costs are accounted for through different avenues, such as special expenses for college.
Since the Affordable Care Act allows carrying kids on your health insurance through age 26, that might be reasonable upper limit for your program.