I think differentnameforthis was quite right to question the school about her dd's reading level - to be on a reading level that far below the one she has suddenly been put onto for such an extended period of time is indicative of a teacher taking her eye seriously off the ball, which as a mother would concern me generally, as I would want to know what else they didn't know about my child that they ought to.
I disagree with ClimberChick about just reading books in the library, though - a mother who knows her child's reading ability well enough to question the teacher's judgment ought to be able to choose appropriate books with her child (unless, as said above, they question the teacher's judgment because little or no assessment has actually been made of their child's abilities in the first place and there is an obvious disparity between their ability to read and comprehend and the level of books they get from school). However, this is said from the perspective of someone who has never had trouble getting her children to read, it has always been their greatest passion, despite being boys, so I just haven't had to think that hard about it, nor have I had to worry that their abilities won't be noticed, because a genuinely fluent, expressive reader is going to be noticed by the school, even a not very good school, provided the teacher does read to him or her at some point.
As for boys switching off in primary school, I don't think it is because they are given reading books that are too easy. Possibly many boys find Biff and Chip too boring as a concept, so easy words or hard words, they are going to be bored by those books. (A trip to the library to find something more interesting might help a bit...). Reading for some of them will only be of interest when they have a good enough reading vocabulary to read instantly exciting adventure stories about monsters, wizards and battles, hence the popularity of the "Beast Quest" series...