As previously described, it’s expected that the kernel times for larger batches take more time (as more work has to be done), but the epoch time should decrease, since more samples/sec should be processed.
Based on the posted profiles:


Densenet121: (20 / 42.710) = 0.468


Densenet121: (60 / 70.324) = 0.853


VGG16: (20 / 50.103) = 0.399


VGG16: (60 / 120.996) = 0.495


so in both cases increasing the batch size should yield a higher throughput measured in samples/sec (or us in this case) assuming the profile is correct.