I have created the lower simulink model for an altitude hold autopilot system as shown in the model below. The model created at the bottom gives the correct answer. The highlighted part is used to calculate the transfer function H for height. I calculated that transfer function in matlab and then used that H function directly in the simulink. The calculated function H is correct as i have confirmed that from the book. However, i get different answer for both models. The lower model gives right answer but the upper model doesn't even come close to the correct output even though the transfer function H is correct. I can't ask my teachers because everyone is on lockdown and i really need to know what am i doing wrong. So please someone help me.