Create one line for each charge, rather than netting unrelated items. Capture the entity that incurred the cost, beneficiary, vendor or payroll source, service period, source amount, allocation driver, approved markup if applicable, invoice currency, functional-currency amount, and recharge reference. Link the governing agreement or current finance instruction.
The allocation basis needs evidence. Headcount may be supported by a dated employee report; usage by a system export; floor area by an approved facilities schedule. If the instruction says “allocate fairly” but provides no method, record an exception. Choosing a method is a finance-policy decision, not a bookkeeping completion step.