What prices does the Trading Simulator use to enter/exit positions?
The Trading Simulator executes simulated trades at the closing price of the last received bar (or last tick price), adjusted by the spread and slippage values specified in the Trading System parameters. When in reality it is not possible to trade at the closing price (for example when using daily quotes and there is no after-hours market), the slippage parameter can be used to account for an average expected price change from the closing price to the next opening price.