Hi Holly. I'm not sure I'm seeing what you're seeing. His responses on 0.4u look pretty consistent, and the other numbers seem to be connected to changes in dose or time.
When you get a blue pre-shot, you can stall for 20-30 minutes without feeding and retest. If the number is rising, you can shoot the normal dose. That might help with some of the inconsistency.
It might be helpful to you to post when you see numbers that are perplexing and we can help make sense of this for you a bit. Understanding the patterns and trends is complicated and can take some time, and we're always happy to help!