When we are creating an invoice or bills (let's assume 100.5 SAR) and the invoice line's analytic distribution is connected with an analytic account as well. 

Let us say the payment is 100 and the remaining .5 we need to write-off to an income/expense account. We have provision in Odoo to Mark as Fully Paid and choose the Income/Expense account there and marking the bill/invoice as fully paid.

Our issues is, the write-off amount is not showing any option to connect the Income/expense amount to an analytic account while doing this process. 

Is it a missing feature or we are doing something wrong?

(We have option to directly check the Journal items with missing analytic accounts and assign there. But sometimes the accountants can forget that and it leads to wrong analytic reports)