Air-freight trading and regional offices
A DAFZ trader of mobile handsets might buy in USD from Asia, fly stock into the zone and sell to distributors in Africa and the Gulf within days. Margins are thin and FX moves can wipe them out, so each invoice needs its original currency, its AED value and the realised gain or loss when cash arrives. HelloBooks does that for every invoice and bill.
A regional office works differently. It may have no sales of its own and instead charge its parent or sister companies for management and support at cost plus a mark-up. Those recharges are related-party transactions, so they must be priced at arm's length and backed by transfer pricing documentation under the FTA's free zone conditions.