Sales Order with Product Costing error must not be saved

Hello Experts,

We have make to order scenario with variant configuration.

Requirement: When we create sales order the product costing is running in the background and if it ends up in error, user must not be allowed to save the sales order.

At present, users are able to save the sales order even with error, although it blocks creating delivery, user is able to by-pass the error by doing Extras->post-processing in sales order.

Hence now we want to restrict the users from saving sales order with costing error.

P.S: We tried using user exit MV45AFZZ with the logic of using table KEKO by checking the Costing status but not fruitful as it requires sales order number as an input to retrieve this data.

Appreciate if anyone can show some light in this requirement.

Thanks in advance,

Jagan.