I’m not sure I understand the datasets correctly, so please feel free to correct me. 
It seems you are dealing with “groups of parameters”, i.e. are these different state_dicts of different models?
Both return 73 million parameters or MB?
What does “My training instead returns 384,420,168.” mean? Does it mean that the number changes if you run it during training? How was it run before?
The last loop loops as if you are printing shapes of data samples from different datasets?