The platform tells you at the moment an arbitrage opp occurs which exchange to buy and which to transfer to to sell. That acts as a bid/ask price. It is not like your average arbitrage system it is designed for cross-exchange
Can you explain how can
last price be used as bid/ask? I wouldn't call it accurate pricing. e.g., what if the last price of $7,000 was for 0.001 BTC, yet the next bid price is $6,500?
If I were you, I'd consider polishing that before presenting misleading info out to the public.