The Line Item Detail - Base Price field displays the Base Price from the item's Inventory database record.
Editing the Base Price on the Line Item Detail screen changes the Base Price for the current line item only. It also changes the Base Price Discount to the right of the Base Price field and the Base Price Percent Discount to the right of the Base Price Discount field. It does not change the Base Price field in the item's Inventory database record.
See:
Line Item Detail Screen Contents
Sales Manager Contents