Actually my previous post was poorly drafted - so I will be editing it - what I should have stated:
Where there is a separate invoice for freight-in, you don’t add any inventory to that invoice but you add the freight-in to the original inventory purchase invoice and then reverse out with a contra account, then the separate invoice for the freight-in gets posted to the contra account to cancel it out.
Original Inventory Purchase Invoice amended for separate Freight-in Invoice
Separate Freight-in Invoice posted to contra account to cancel out separate take up