i must be losing the plot...surely if you reduce your gross profit you're reducing your net profit?and which markets have a % under 100%?
Gross profit and profit after commission are both reduced. But, as long as the overround is small enough, then contribution towards EF is greater than the value of profit lost, leaving you net net better off. This is because half of implied commission is greater than half of commission.
as long as the overround is small enough.... Would your churning work if you have two accounts, lay your own bets across accounts, zero overround, no betting losses, just commission on each account.