I'm pretty sure, I know the answer to this one, but I'll give it a go anyway.
I'll just throw random prices in here. Let's take a market with only two possible selections.
Selection 1 has a current best back price of 1.70 and best lay price at 1.72. I put in a lay bet at 1.71
What I'm asking for is essentially to back selection 2 at 2.4084 ish. Betfair pops my requested price for other to back at 1.71, obviously, but also for others to lay at 2.42. If someone takes the latter price, and selection 2 wins, I win 1.4084, and the counterpart loses 1.42. What happens to the remaining 0.0116?
I've always assumed Betfair just scoops up the difference along with their commission? But I might be missing information as, I'm a 95% of the time offering a price type of trader, as being discussed elsewhere on here. So it might be that the "giving the best price" extends to this, and you sometimes get a marginally better price than asked for?
