Weight price calculation in back office - possible or not with decimal numbers?

[Inspirimental]

Dear Prestashop Community,

for a team of butchers I have implemented an individually developed online store (incl. payment API, order management, item management, financial accounting export, etc.). Since in the future there should be more features like customer account, voucher management, DPD / DHL API, etc. I wonder if a store system like Prestashop is the better alternative than developing everything by hand. In Prestashop many functions can be added with just a few clicks. I already installed a test instance of Prestashop and tried out various functions. The online store is absolutely sufficient and the order management in the BackOffice is great and clear. I also really like the customer login. Here I think Prestashop is an excellent option.

My Problem:
In addition to the onlineshop orders, manual orders (telephone inquiries, delivery to supermarkets, etc.) have to be entered in the back office order management. For these manual orders, there is a special feature needed. The butchers need to add kilo price items in addition to the normal item variants. This means these items are chosen from a catalogue (like a normal item variant) and the attached kilo-price is shown. As soon as you enter a quantity (decimal number like 4.352kg) the base article price and the quantity are being calculated.
E.g. beef tenderloin 49.99€ / kg * 0.894kg = 44.69€

Important: This functionality is only needed in the back office not in the front office.

My first attempts
I was able to find a base price in the PrestaShop item management. However, I suspect that this only serves as information for the output in the frontend Onlineshop. When creating items in a back office as manual order, it was not possible for me to calculate with this basic price. Also I could not enter a decimal amount.

My questions are
1. is there a possibility to enter order items with quantity and price per kilo (basic price) in the BackOffice? If no, can this functionality be developed via a plugin?
2. is it possible to enter decimal numbers in the back office order management?
2. are free positions (without article reference) possible?

The two screenshots show my current development for my customer. The screenshot for processing an order shows the three different positions with article variance, basic price calculation and free position.

Thank you very much for the information exchange.
Best regards

Tim Beck
---- Inspirimental ----

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Edited October 26, 2022 by Inspirimental (see edit history)