Hi Jörgen
Thanks for the suggestion,
but I alread have that extension as I had purchased bundle from Breakdesigns
Unfortunately it's not suitable for my purpose.
It requires too much extra steps because for each product I would need to create custom field and create pair with it and product which is named "Bottle returning fee". It also doesn't look nice because it emphasizes "Return fee" as additional product.
For this purpose Tax Calculation Rule "Price Modifier After Tax" is almost suitable:
I created it, and named as "Bottle returning fee", Math operator: +, Value: 0.5
and if I apply it to final price, it changes 44.5 price into 45 as it should be.
But:
- it also changes VAT tax from 8.9 into 9 which is not good for this purpose
- it adds column named DISCOUNT, but that could be mitigated by renaming language phrase.
My next goal is to find a way how to make that VatTax doesn't include DATax
which means heavy digging through calculator functions

Regards