It’s not quite as bad as that - see my other comment; the calculation of the charge doesn’t mean you pay 5%+60% commission on winning bets. That kind of fee would be impossible to sustain, no-one has that kind of profit margin on their betting. The commission % charge and the PC % charge don’t work in the same way.

On the flip side, a great many people pay far higher than 60% of their net profits to Betfair... most will have paid over 100%...