After the strategy calculation of all signal bars on the historical data, the strategy proceeds to calculation in RealTime mode. In case of the historical calculation: Environment.IsRealTimeCalc = false, and in RealTime: Environment.IsRealTimeCalc = true. The key difference between RealTime calculation and historic calculation is that the sent orders at historic calculation can be executed at any possible price within the bar. In RealTime it happens only on the ticks received for the symbol.
Strategy signals calculation in RealTime is executed in the same way as historic calculation, upon the close of the next bar in sequence.