This is a typical issue of underdevelopment or underexposure, whatever it is, your negatives are too 'thin', not dense enough... so when scanned or digitally photographed those weird tones appear, I can see it in the over emphasised dust on the original image, also if you bring that image to photoshop or similar and play with the curves (contrast and blackpoint) you get something very similar to your second example.... the point is: the second sample you posted will have exactly the same problems as the first, you are just hiding them with the contrast applied to the digital file..
So the problem here is you are either underexposing pretty bad the negative (shooting 2 or 3 stops under what one can call a 'good' exposure) or your temperature or dev time is lower than what it should be..
Try to find a properly exposed negative and compare it to yours, do you see a difference in regards of density?
Google for 'thin negative' 'negatives are too thin' or something like that....
Underdevelopment can surely be something. I don't think it's the camera that underexposes everything. I have checked the meter readings with a handheld and also tried another camera with the same results. The time is right as well if not my iphone got a really bad stop watch app. But my thermometer can be a bit off, it's not the most expensive proffesional one. I will have that checked against a couple of others.