That is just a standard letter. That is what ours said for QM and AGS. The caveat is 'because of the girls who won't take the place'. I know it's hypothetical but how can the school guarantee that some of the girls in original PAN will drop out. What happens if they all have it as their first choice on the CAF?
Because some always do - can't quote exact figures but some of the schools who have ranking may have 140 places say and end up offering down to 220 or more... Some schools try tempting the top X kids by inviting them for special open days, reminding them that they are high scorers but still some will be high scorers elsewhere too and will there instead.
PS here is a bit from last year about HGS :
I also found this information on their website regarding the ranking at Handsworth Grammer Boys which they too informed me the same.
A. Children have been put in order of performance and the rank gives their position. If the boy’s rank is between 1 and 289, they must have been given a place at a School higher on the preference form.
B. If the boy is ranked between 289 and 388 he will be on our waiting list.
C. If the boy is ranked between 389 and 900, then he has not reached a standard suitable for entry.
... bear in mind this was after allocation day and there aren't 289 places there