@SAitchy, it is pretty high on my todo list.
@alasdair, I wouldn’t be too much concerned that zero quantity is not how it’s shown on purchase invoice. Logically speaking, the purchase invoice was for freight of inventory item(s) only. So when categorizing this purchase invoice from accounting point of view, your quantity has increased by zero, value has increased by freight cost. So that’s how it should be entered.
Consider this, purchase invoice could be a single line item of $1,000 but you know that it is for freight of 3 different inventory items. So even though purchase invoice was single line item, you still need to split it into three different line items so the correct cost can be attributed to each inventory item type.
It’s not a big deal if line items on paper invoice don’t match how it’s recorded in your books. It’s common not to match (companies which split common expenses among divisions do this all the time). Your supplier sees the invoice as simple freight income, for you it’s capitalization of one or more inventory items.
The only important thing is that purchase invoice total on paper invoice and in Manager must match and that condition will be met.