UI Plugin and Custom Discount Field to calculate Net Sales Price for Zero Quantity Products

summary currently there's no way to influence the net sales price of a zero quantity product (i e usage rate product) when using either the standard discount fields or a discount tag to workaround this, i created a ui plugin and custom discount % field that will calculate and update the net sales price bonus highlighted how i like to flatten the ui plugin line items to more easily traverse the possible nested lines (parent bundle, child lines, ramp lines, etc )