How can I modify the theme to display a price per unit?

[justivo]

I am in the process of converting an old WooCommerce store to the latest PrestaShop and I've hit a snag.

In the old store, I can show the prices per unit type, but I can't seem to do the same in PS.  As an example, an article that is available in different combinations, when it's just a single 140gr pack I want it to say 9.64€/Kg, whereas when it's 5x140gr packs I want to say it will end up costing less by showing that it will be 8.93/Kg.

In PrestaShop I can't seem to do this sort of thing, even by setting the "Impact on price per unit (tax excl.)" field on the combination's page.  I assume I will have to do some sort of calculation directly over the theme, but I'm not sure what theme variables are involved either.

The above is what I currently have which gives no feedback to the user about the different prices per combination.

I can't seem to find anything relevant in the PS documentation either.  Help, please?

Edited August 7, 2019 by justivo (see edit history)