While you are correct, it also isnt good practice for a firm to be doing what FF is currently doing.It may not have been.
They may have had a benchmark score for written app of eg. 75 but someone who scored 90 and 90 scores higher than 99 and 75 for example. Or indeed this is where they decide someone scoring 99 from Oxbridge scores similarly to someone scoring 80 at a less competitive uni.
Requesting SARs of firms won't win you friends and won't change the outcome. Why put yourself in the position asking for a SAR and confirming to them they made the right choice not offering you a place. I despair of some of the suggestions in here.
It is simply a numbers game with them I suspect getting 4000 applicants or so.
People spend hours, days on their applications, practicing WGs etc. working around work or uni. Being told a 98 percentile score isnt enough for you to get through to the next stage without any actual explanation is a bit ridiculous.