They do sound a bit on the high side, not inconceivable but rather high unless you are an Olympic class athlete. 300w average for 2hrs is pretty impressive from a gonzo point of view. 12k mi per year is certainly a professional level of riding. Your recovery must be equally impressive to allow you to function in grad school classes. Might do to get an independent check on the heart rate setup to squelch the doubters in your class. Do you ride competitively?
Steve