My dd who is in year 3 did some test a few ago at the beginning in her new junior school. I understand/think that these are optional sats. She got level 2C in her reading although she was a 2A in her KS1 national sats. She was a 2C at the beginning of Year 2. I asked the teacher as to why there would have been a two level drop and she explained to me that the ones in Year 3 are much harder and would have been a challenging and shock for most of the children. She showed me an example paper and the sort of questions that they asked and how different this would have been to a KS1 Year 2 sats.
I then asked what her target would be for end of year 3 and which I was told would be a level 3C but she also explained that there would be more of these test prior to the xmas holiday and children are moved around when necessary.
In Maths she got a 2B which didn't change from KS1 Year2 NATIONAL SATS.
I would therefore want to find out if this is an ok level or below level to be at and whether these are the ones that the school would determine or set targets for year 6. There seems to be not much information regarding the levels of optional sats levels.