Facebook Purchase Conversion Value

We've recently increased the e-commerce events we're tracking with the Facebook pixel. 

This has caused the metric we were previously using ("Action value") to be inflated with the values from cart adds etc, but I can't find the value which matches with the one called "Purchase Conversion Value (Facebook Pixel)" in the Facebook admin.

So, by question is – which field should I use to match to the one called "Purchase Conversion Value (Facebook Pixel)" in the Facebook admin. I cannot find this as an API value here: https://developers.facebook.com/docs/marketing-api/insights/fields/v2.8

OR is this somehow not available in the API and we should stop tracking values for non-purchase conversions?