I want to know what is the difference between Rate and Price List Rate. I have been always using “Rate“ as the option. But I want to know how does it affect the PI or SI, when “Price List Rate” is enabled.
ERPNext save item costing and selling rates as Item Prices within Price List depending upon either setting are enabled in stock settings doctype.
Item Prices are like pre set rate which can be made read only to be controlled on transactional level. Item Price is not the finalized transactional rate as margin and discount functions can be added or subtracted to reach to a finalized transactional figure and that is what Rate is.
So the correct flow in ERPNext becomes:
Item Price → base reference Margin and Discount → adjustments Rate → final transactional value
When you record a Sales invoice and insert any item, it fills up price list rate field. Incase you offer any item level discount will be deducted based on price list rate and will contribute towards a finalized rate for that item as following;
Upon saving ERPNext can update item prices as a new setting in stock setting doctype offers to update item prices based on either price list or rate fields derived originally from transactional doctypes such as sales order or sales invoice (for selling rate). The same case works for costing rates on buying cycle as well.