Need help for a suggested way of overwriting the default PRICE_LIST_NO value on the Postings Tab.

Thought I could do it by using an event, but not sure exactly how that code would be written to function as intended.

Function needed:

When new posting lines is added to a Work Order in the “Postings” tab, each line pulls the Preferred Pricelist from the connected Customer, using that Customer’s Price List value. 

Problem is that the same Customer can have more than one Service Contract (and more than one Object / site), but with different service types depending on the Contract. Therefore we need to be able to pull different Price List No values on the same Customer, why the Price List or Customer Agreement is not fully enough to create proper sales price invoicing. 

So what I’m looking for is a way where the standard Price List No value can be overwritten to another one, using an Event, if fx the Service Contract Type connected to the Work Order has a certain value, and then overwrite the Price List No with a new value, if the criteria is met.

Example:

Work Order is in Reported status.

New postings is added.

Posting Lines will get the connected Price List No and then choose the Sales Price from that.

Service Contract connected to the Work Order is a “Everything should be invoiced at standard price rates”, but the Customer has another tier Price List connected as default. 

Therefore the default value when adding new posting lines, should then be overwritten with the new Price List No, so the sales prices is updated correctly, matching the Service Contract intentions.

In the screens below, its the colomn named “Foretukket prisliste” (danish, sorry) that’s the “Preferred Price List” (Price List No). Here we have a list called “DK_FSV” as default per Customer ID pricelist. But the Work Order comes from a Service Contract, where we want to use another Price List No instead, that has other prices, fx a Price List No called “DK_UA” instead.