Simulation software uses "typical" spec's for parts. A typical or better device will work in the circuit but a device that has worse spec's or a maximum spec but still passes might not work. You must analyse your design to see that even devices with passing but poor spec's will work properly in the circuit. Adding an emitter resistor to a transistor so that base-emitter voltage differences do not affect the circuit or having enough current in a voltage divider that biases the base of a transistor irons out the differences in current gain.
The current gain and base-emitter voltage vary between transistors of the same part number.
