Unless he sat a full SATs paper each time his level was assessed, it's likely that these sub levels (especially the jan one) are made up. It's not a science, it's not even an art, it's a tick box exercise that should be taken with a large pinch of salt.
Yes experience does seem to help. Thank you for sharing yours. I probably need to make better mental notes of the things you identified under impressions gleaned. Enthusiasm is the trickest one, as there doesn't seem to be enough of it!
If can I see for myself that they're learning & have learnt, that they've improved from where they were in past. What is the general trend, allowing for occasional plateaus and spells when something else (like social skills) may need first priority. It's not that the assessments are useless, but I'd think they're just one little bit of info.
Impressions gleaned from: homework, things they say about what they've learnt, non-academic activities (how things like thank you letters improve), math riddles that come up in daily life, art work, academic work sent home, marking on the academic work, questions they ask, observations they make, etc. Also how much enthusiasm they muster for learning even more.
And even silly things like what ability group they seem to be in; obviously I worry more about progress if they're near the bottom than near the top.
What the teachers say about them; you can tell when a teacher is frustrated or delighted by a child's effort & progress, often without teacher having commented directly on either.
By now I've got DC4 at school so I've a pretty good idea what typical progress looks like in lots of areas. Experience helps.
IMHO (and it's only opinion, not expertise): Neither the assessments nor the expected progress rates are all that reliable. I prefer much more qualitative ways of verifying that DC are making decent progress for them.
Ds Maths was at Level 4A in January. The expected year end target was 5A. In July his level was 6C. This progress seems unbelievable - is it likely? I thought that 2 sub levels was generally expected over a year. I would add that he has complex SEN and concentration difficulties and was only attending part -time so missed 1 maths lesson per week. He was also excluded for 4 days and sent to a PRU which meant missing a further 5 weeks of lessons during that period. Any advice would be appreciated.