Discount rate

It's the rounding up. If the 5% comm is equal to 23.5p they'll take 24p and that's more than the 5%.

Funny thing is, it went down to 4% today before going up to 6%

Good grief it's gone up to 8%

Are these very small bets? If winnings are 10p, you'll pay 1p (10%), 11p=(1p,9%), 12p=(1p,8.5%) etc.

My mistake, I thought betfairs commission had increased to 8%. Rather than been dicounted by 8%.

Brain fade, my bad......