custom 'custom field'

[rudders360]

Hi all,

hoping someone can point me in the right direction im a novice coder so please be take that in to account with any responses thanks...

The problem...
Im using product packaging units when setting up products. Ive managed to add custom units to suit my need like serving, sachet.
I then use custom fields to enter cart variants. I don't want to use child variants as I don't want a page refresh every time.

when the price changes from the cart variant selection the price / unit also changes. I don't want it to do this. I would either like this cost per unit to stay static linked to the initial product price

OR

I would like to be able to do another custom field that will calculate this correctly based on other cart variants and bypass the product packaging field.

Scenario...

product: Food supplement.
Parent:
custom field: product weight cost
custom field: servings

and the bit I need help with...
custom field: cost per serving: (adjusted price based on product weight, cart variant selected / number of servings)

Can anyone help please?

Thanks in advance.

[rudders360]

^^ Friendly bump ^^

[balai]

Why the "cost per serving" needs to be a custom field?

The product prices cannot work like this?