We only NEED Reading Recpbvery because the initial teaching of reading - using mixed methods - has failed so many children.
I do know what you mean, but I would say that in that situation RR is the very last thing a child would need as it is only more of the same stuff that has already failed them.
You will, I'm sure, be interested to know that RR, in a very clever move to make sure that their highly indoctrinated trained teachers are never short of a job, always work with the 6 'weakest' readers in the year group.
Think about it, you could have a Y1 cohort where every child is reading, say, 6 months or more ahead of their chronological age. There will, inevitably, be 6 children who have the lowest reading ages, so they will get RR. And, because they were reading absolutely fine before they had RR they will appear to have improved at the end of RR and they will go down as a 'success' for RR. if they've been taught initially with good phonics instruction RR will love that even more, because then they can be classed as 'struggling despite having had good phonics instruction' (which, of course, makes SP look bad). RR is such a devious operation..
On the other hand, if a proper cutoff point was fixed, say reading at 6 months below CA, RR would have no 'customers' in that particular school! One expensive teacher out of a job...