Im trying to configure a service product pricing on Odoo 14 Community where:

1. The product must have a fixed base sale price, e.g. price per vehicle

2. The same product will add extra amounts per persons (or uom), e.g. extra amount per passenger 

Tried to configure an attribute with a single value for the base product and configure the "fixed base price" (price for the vehicle) but once you add quantity (which are the passengers) then the price is calculated as:

Price = (fixed base price (vehicle price) + price per Unit (passenger)) * QTY 

while the desired calculation is:

Price = fixed base price (vehicle price) + (price per Unit (passenger) * QTY)

Any ideas?