SOP is usually 5x60 for OG or Wilson reading. Some research suggests that similar results can be obtained from 2x60. My Wilson-certified colleagues mostly prefer at least 3x60 for elementary grades, and 3x30 for secondary. 3x120 is quite a lot for a 6 yo, in terms of the length of the sessions, but not far off the norm in terms of total minutes per week. (Is that both reading and writing?)
Public school might be more willing to let him miss 6 hours of school a week in consideration of not having to pay for the therapy themselves, especially if they don't have a Wilson/OG-certified person, or if the caseload is already a bit crowded.
