Split, process, and reassemble

Finance needs each order back as a single object with line-level math you computed while the items were split out. That means expand, calculate, then bundle everything under the parent order again — the full split-process-reassemble cycle.

You'll import orders with nested items, use Split Out to explode them, add an Edit Fields node to calculate line_total from qty times price, then use Aggregate to collect everything back into a single structure with the new calculated field.