DD did 200 minutes a week (40 min/day) Orton Gillingham at school on an IEP for 4.5 months at the start of 5th grade. Her phonological skills went from kindergarten level to 100% accuracy on all tests, and her spelling improved by something like 4 grade levels, from a bit below grade level to well above. A combination of tutoring and push -in services for writing brought her well up as well, but she still has IEP goals on writing.