**What**
- fix `difference_due` in the OE modal to show the correct difference a user has to pay
- fix Timeline crashing due to returned line item being `undefined `(deleted after OE confirmation)
**Why**
We were taking into account `refunded_amount` when calculating "Difference Due" and used the following formula:
`orderEdit.total - paidTotal + refundedTotal`.
The issue here is that `orderEdit.total` is "overpriced" for the amount of items that are returned/refunded already (i.e. we are charging the user again for the returned items).
The straightforward solution would be to subtract `refunded_total` from the `orderEdit.total` to get the total cost of items the user is actually getting after the edit.
`difference_due = (orderEdit.total - refundedTotal) - (paidTotal - refundedTotal ) = orderEdit.total - paidTotal`
But if we have partially refunded returns, we would have the same problem of returned items priced into the total.
In that case, general solution should be something like:
`diff_due_display = orderEdit_total_of_items_user_is_getting - paid_total + refunded_total`
Would like to hear what you guys think!
---
FIXES CORE-1246
bd199d7f44