Well if it helps, I'm pretty sure I had about the same SAC average as you, and I ended up getting a 44.
I got 100/100 on the oral exam and 14/15 on the writing section but a a bit worse on the reading and listening sections (I don't remember exactly, but maybe in the 75-85% range? I'm sorry I don't remember exactly.
In my opinion I really think it's a lot of chance over about 40 as to where you're going to sit because you're French level should be above what the exam can test. Remember that I likely wouldn't have got much of a better score even if my French was 10x better (I'm sure I made mistakes in every section and I don't believe they made a difference). Once you're French is at this 40s level, sadly it mostly comes down to exam technique and a bit of luck (aka being able to work out what on earth some of those listening and reading questions mean, I couldn't...)
So basically from what I've seen they're not marking 0->50 as "no French"->"native" as that's not what's in their marking criteria. It's more like "can barely do anything with the text and topics given" -> "can do everything we're asking for with the texts and topics given, is psychic enough to read our questions that are very confusing and shows at least a very-very-good-for-a-non-native-18yo level".