PO with single & multiple account assignment

Hi expert,

I got one PO with single & multiple account assignment. How should I book invoice. I try using MIRA for items with multiple acct and MIRO for items with single acct. I works but can I do it in one shot instead of splitting. If so, how?

One more thing: if I got invoice saved in MIRA but without any items. It can't be changed. It say it is schedule by background. How could I change it?

Thx