The results are worse than they look at first glance...

I had a bank that I only put $100 in, but my total turnover is over $700, giving me just over 7% profit on turnover (which is more relevant than my starting bank).

So I've never 'topped up' my original $100 but it, along with the winnings, have been invested again and again giving me a total outlay of $720 and a total winnings of $772.

The profit on turnover figure I think is the most relevant, even though you do need to have a large enough bank to cover bad runs - Melbourne Cup & Oaks Day were EXTREMELY bad for me...