I had to read this a fews times, but I think I know what you are asking...
Meaning if I worked out for 1 hour and felt near the bottom of the tank at an average heart rate of 140 and the monitor showed 900 Kcal's versus working out for 1 hour at an average heart rate of 140 but not feeling depleted did the first example actually burn more calories?
Both burn the same calorific total, the latter will burn less fat calories. The relative contribution of fats to total energy output is inversely proportional to exercise intensity, and a low to moderate exercise intensities its also proportional to muscle glycogen depletion.
When talking about 'the tank' I am refering to muscle glycogen stores, not liver glycogen. Exercising with low liver glycogen, unless you are ketone adapted or fueling on the go, will lead to an early knock and curtail workout capacity. I suspect that following your second workout, because you delayed eating, your liver glycogen stores will have been low following the workout, and then continued to deplete into the used muscles. When the liver empties too much, IME, a ravenous hunger ensues which seems to dominate all powers of self control... its linked with other hormonal triggers like ghrelin etc.
The key - train low, but dont entertain extremes. I will post more later on this...as usual I'm pushed for time...