Your output seems like its more expected. I’m also running on Xavier. I tried both PyTorch 1.9.0  and 1.8.0 and seeing the same results. (The nn.Sequential() is alway significantly higher)
This is the output I get for conseuctive runs of the program script above.
:~$ python3 test.py
11.383225899993477
3.725462199993975
176.9323086999994
:~$ python3 test.py
5.979387333337627
3.1348664666647132
77.57876950000575
:~$ python3 test.py
5.478009166661953
4.854251033331518
105.16439119999556
:~$ python3 test.py
5.193072766667228
2.5191012333304266
135.01443140000143

Any ideas to narrow down the cause of issue?