How to restrict manual adjustments in sales order for lines already adjust in quote?

Hello everyone,

I have some troubles to find the best way to do restrict manual adjstments on the sales order form.

Here is the situation:

Sales order are created from quotes exclusively. On the latter, it is possible to create adjustments from the modifiers that already exist.

It goes from fixing a price directly for an item or applying a discount on one.

Once the quote completed, we approve it and transform it into a sales order.

However, on this sales order, it it still possible to modify prices of  from the View Adjustments form made but also to delete them or add new ones.