Conversatio Rating Agent Attribution API

Hello there! 

I am having some issues to understand how to assign the Conversation Rating to an agent. 

Context: I am using Fivetran connector to load the data on our Data Warehouse and from conversation_history table I am grabbing the column conversation_rating_teammate_id to link the owner of the rating with the corresponding admin/agent. 

Issue: We want to attribute the rating of each conversation to an agent using the same logic Intercom is using in the UI where the last agent who respond get the credit but for some conversations the last message author ID from conversation_part_history is not the same as the conversation_rating_teammate_id. 

Can someone explain me how this attribution logic works?

Thanks!