It sometimes happens that the selling price including VAT of a product has no direct relationship with the price excluding VAT. Similarly, the selling price of different variants of the same product may be different and result from various combinations.
Proposal
I suggest creating the following fields:
product.template
retail_price : on the model of the list_price field, this price will be a price including tax and will serve as the base price during a sale with a price list including tax.
product.product
markup_price : supplement that will be added to the template price (list_price or retail_price depending on the selected price list) of the item to give the base price of the variant.
The base price of a variant before the application of the tariff will be:
For me it is not the only way to modify a price per variant, it could be done with a percentage for example. So for me there are too much possibilities that I prefer to stay as customization.
Does not work with classic sales and with tariff. Maybe detach it from the point of sale to make it a separate module.
Yes there are a lot of possibilities. Many are supported by price lists, in particular all those that have a “calculable” relationship with an existing price, there are still cases without this type of relationship.
For me the POS meets a specific need: the products, the seller and the customer are gathered in the same place at a given moment.
There remain all the other cases where it is necessary to manage a sale as in B2B but with B2C prices.
Indeed sale point does not extend the price list module to add the gross price in the evaluation context. This is quiet logical as sale point is not designed to work with price list (future improvement should make sale point working with promotion). But again I think your requirement is specific because we can not implement all the possible way to compute a price.