When making a teacher judgement, one must look at the whole picture and consider all of the evidence. In maths, this includes: test outcomes, observations, and learning conversations. It is important to look closer at the NZ Curriculum Maths Standards. When making an OTJ, you need to remember to look at the WHOLE standard, even though the number expectations are critical. Number Knowledge is for facilitating problem solving, and it should not hold a student back on the standard. It is important for students to be working at that standard independently and most of the time.
Don't forget to 'clean the dirty data.' It is important to know why students are given the OTJ that you have chosen. It is also important to be consistent in the reasons you have chosen to give a certain OTJ.