For that specific example, it was a bonus bet of $150 at odds of 5 if Im correct.
So you have won into your bookmaker a total of $150 x 5 = $750 return. Then deduct your stake as its not returned so we have $750-$150 = $600 won into your bookie account. And $487 lost at Betfair.
So your profits the difference of the two.
That make sense?