they are different. Quote is for 1 piece price + other charges. Estimate is for total quantity to be ordered. The gross total amount of the Estimate is the amount payable. Replacing Estimate as Quote is not understandable because they are different. In other words, we send a quote normally via email and when the price is approved, customer confirms quantity and an Estimate based on the quantity is sent. Customer releases PO as per Estimate not Quote. Once PO is issued and accepted the final order value is decided. This is Estimate and not Quote.