What happens when he reads a word he's never encountered before? Does he decode it nearly accurately? I have two stealth-dyslexic kids, and my oldest reading level was so far beyond what had been assessed in school that no one heard her tackle a new work in reading after kindergarten. She now describes having learned two different languages growing up: spoken English and written English. When asked to read aloud, she would translate on the fly.
My two stealth dyslexics each somehow score ~50th percentile on the CTOPP, but with modestly mixed scores (~25th-75th percentile). The scores in isolation don't sound any alarms.
My kids demonstrate their difficulties with the WJ language testing plus the supplement Spelling of Sounds in Words, particularly setting the contrasts between word attack and spelling in comparison to reading comprehension.
The TOWL has also been useful to demonstrate spelling in contrast to vocabulary.
None of these were particularly great for progress monitoring for my kids, though. We've gotten more from various Orton Gillingham-based spelling progress monitoring, which differentiates between learned words and decodable words for spelling. They don't provide a percentile or grade level, but instead an accuracy rate, which can be compared pre- and post-intervention.
