Browse vs Cart vs Checkout Abandon

Hi

We appear to be having a problem with out Cart Abandonment flow. I think there is something wrong with the add to cart button signals.

I have created three segments over 30 days;

1. Checkout started and not placed order in 30 days: 3359 profiles
2. Added to Cart and not placed order in 30 days: 687 profiles
3. Viewed Product and not placed order in 30 days: 27800 profiles

I would have expected Added to Cart to have been higher than Checkout Abandon.

( we are on shopify )

Thanks for reading this..

Sean