This PosSizer implements the concept of trading market's money: the total account equity is divided into two parts, the starting capital value and the profits. You take smaller risk on your starting equity and larger risk with your profits.
The PosSizer uses one of the Wealth-Lab's three standard choices of sizing trades, i.e. fixed dollar, percent of equity, or max pct risk, and increases the size by a specified percentage (default: 100%) when risking "market's money".