In numbers:
You put in 100 cr, WGT takes 10%, results in a wager of 90.
Same for your opponent => a wager of 90.
If you win, you take 180, you gave 100, this is showing in your account.
Net result is +80.
If you lose, you gave 100 and get nought => -100.
See account.
Total rake is +20 for the company - the calc is even.