Bunker Lifting- Create new line for each lifting instead of sum up the quantity to the existing line

If we have a bunker lifting for a port, pay the invoice and post, and later register a 2nd bunker lifting, that 2nd lifting quantity is automatically added to the one already paid.
Sometimes we have a 1st bunker lifting paid by operator and a 2nd one paid by TCI owner, and as the last lifting quantity is automatically added to the previous ones, there’s no way to separate the liftings and the accounts (paid by operator or paid by TCI owner).
The current workaround is to reverse the invoice, edit the bunker liftings inserting the correct values in 2 lines and indicating in each line if it is paid by Operator or TCI Owner, and invoice again.
Reverse the invoice and recreate it all time the issue happens is not a feasible solution for us.
This is the behaviour we expected:
As the lifting is already invoiced, if we receive a new lifting we consider that a new line should be added on bunker lifting section, not sum up the quantity to the previously existing line which is already invoiced.