excellent post pagwatch.
I think 6 books a week is far, far too many at reception level. it's not too bad at levels 1-3, but once you get to level 4 and above the stories become much longer, and expecting a child to read one of those a night would put far too much pressure on IMO. The children in ds' class get two books a week and I think that works bell, because they are encouraged to look at the book, talk about the story and the pictures etc, not just read it and give it back, iyswim?
Also if you do a straw pole you are far more likely to get the competitive parents coming out to tell you their children are on level 4/5/6/reading war and peace in their spare time, and the more of those you get, the less parents whose children are on the lower levels will have the confidence to come out and say it, because like you they will assume their own children are obviously behind compared to the majority of others, when in actual fact the number of children on the higher levels is more likely in the minority.
Also, you will get parents who will lie and big up their children - I know one parent at our school who has been going around telling other parents that her dd's reading is so advanced and that she is actually being held back by the other children who are just not as good as her. And that is absolutely not the case.
I help out in a reception class once a week and I can tell you that out of 30 children there are only 7 who are above level 4.
And to me the child who can read fluently to me at level three is no less capable than one who is reading fluently at level 7. It's the fact they can do it that is relevant, not the level at which they are doing it, because ultimately they all catch up.