Contracted Prices are stored on line items when adding products to an Existing Business Opportunity through the line item editor. Contracted Prices are also known as "Purchased Price" in the Quote Line Editor.
In this example below we can see three products that were previously purchased and show a Purchased Price.
When these products are added, it will automatically apply the highest discount to the line item. In the background it will apply two elements to the Quote Line item:
QuoteLineItem.tysoxrr__Contracted_Price__c = $ value of the per unit price it was previously purchased at.
QuoteLineItem.tysoxrr__Contracted_Price_Entry__c = true
If the price stays greater than or equal to the Contracted price, the Contracted Price Entry field will remain as "True". If the price drops below the threshold, Contracted Price Entry will be set as false. For display and reference purposes, the Contracted Price will remain on the line item.
Contracted Price Entry line items where the value is "True" is excluded from approval discount fields. Definitions for those fields are in this article.