It is for the panel to decide what they think of the head's recommendations. My guess is that they might be confused.
So was I, which is why I waited for Etienne to answer first.
(I am a coward at heart!)
I will admit that the 5/5 on 3:3 is possibly the oddest ranking I have ever seen! If you have a chance to speak to the Head between now and your appeal it could be interesting to ask "just out of curiosity, and I know what a difficult business it must be" which criteria s/he gave most weight to when preparing the recommendations.
The Heads are supposed to use many factors when drawing up the recommendation, but we have already seen a number of examples this year where they clearly haven't followed that advice.
My guess is that s/he relied on one factor much more heavily than others, and that has produced this very odd distribution of results. I am thinking particularly of predicted SATs, which may test learning to date but not VR ability, which is mainly innate, not learned. From your post on the other thread it is clear that the school is under-achieving in SATs results compared to the Bucks average, so there are perhaps some bright pupils who are not being well-served at the school. That could help you explain to the panel what has gone on here.
I wouldn't worry too much though. With a score of 120 and a 1:1 recommendation, your DD was still deemed to be ideal GS material - top of the list - and you do not have a lot to prove with a shortfall of one mark.
Just make sure that you are putting the best possible academic evidence in front of the panel.