Create negotiation without Lines

Hi,

We have a requirement to create negotiation without lines, we tried disabling all the line related elements in the negotiation style, but still when we create new negotiation, lines are mandatory and system throws error to enter atleast one line. Also, per our requirement customer would like to get quotes in percentages, example customer will share rates and on top of it suppliers will share their response in percentage and in some cases suppliers directly provide their responses in percentages instead of response price. To handle these types of cases, we wanted to create negotiation without lines and lines to