Linked Number Columns with Formula

Hello, I want to achieve two number columns that are linked like a formula column, but both editable. This will be used for linking ‘Price (ex. VAT)’ and ‘Price (inc. VAT)’ columns. One 20% higher than the other. That way I can enter

I have tried Auto Boosts automations to copy the number from one cnumber column to another number column with a formula. This did work, but has limitations:

The problem is that I use these columns in a Purchase Order board as a mirrored column in a subitem, and when I update one of the prices from that PO board, it does nothing:

At least not until I click on the original board. It seems like the automation doesn’t trigger until then. That’s why I would like more of a formula column so it will always work, but it just needs to be editable.

Appreciate any help, thanks,
Joe