CELPIP score changes CRS by a large margin?

I took the Celpip exam and got R 12, W 8, S 9, L 11.
With two years of work experience, a Masters degree in US and no relatives in Canada, my CRS is at 405.

If I retake CELPIP and improve writing to 9, my CRS gets to 450 and if I improve speaking to 10 along with writing, CRS gets to 456.

Has anyone else experienced a similar situation? Why is a single point effecting CRS by such a large margin?

why don’t you go with IELTS

I preferred Celpip because the test duration was short compared to IELTS and it was easier to book a slot. And now since I am familiar with the format, I will retake it and prepare for it better.

The points for " skill transferability factors" will be affected if you don’t meet the CLB level 9 in language proficiency. The points for education and foreign experience gets doubled when you score above CLB level 9 and this is the reason you noticed the big bump in crs score.