Settling losers affecting commission?

I had a bet on Aberg to win, and I have also layed Scheffler.
My losing position on Aberg prior to the cut ate into some of the profit on Scheffler, and as it was the same market I would expect not to pay any commission on this portion of scheffler winnings until I was in profit.

However, now Aberg has been settled as a loser my book looks like I will be paying commission on all of any Scheffler profit. It's like they are now counted as separate markets.

I could be wrong, and honestly I expect (and hope)! to be but am unable to work it out.

Figured someone here might have experience of this as it must be pretty common scenario, thanks.