Producing a boost converter, difference with theoretical analysis
You need everything to match. The 72 Ohm resistor load guarantees that Pout will be 200 when Vout is 120.
The problem is that Vout is less than 120V. So increase the duty cycle slightly until it reaches 120V. I guess you calculated the duty cycle neglecting losses, and consequently, you came up with a too low duty cycle to get the desired output.
Please note that a boost converter typically is designed to produce a specific output voltage. It does not (usually) regulate power or current. Also, note that the load puts limits on the relationship between output power, current and voltage. The power source (your boost regulator) is not free to adjust all three parameters (output voltage, current and power). The load imposes limits on them.