My DS (5) reads pretty well, blue band book are pretty easy maybe one or two mistakes, green level with a bit of guidance.
Today he picked up and read Dogger, read it really well, it's a library book so not read from memory. So I tried him with a couple of ladybird books, chicken liken, little red riding hood. He can also read them with a little bit of help with long words. ( no more help than the green level)
Why? Do you think he's just a bit more engaged with them? have I wasted money on all the scheme books