Some history is required here I believe. The first high level competitive use of DNP was for Mr. Canada in 2002. It was part of an elaborate biochemical optimisation. Idea from use came from a renowed pharma book where it last appeared in the 1970's (Goodman & Gillman, yellow edition). The pharma literature reported that it provided for a linear increase in body temperature with dosage. That information, very intuitive, is incorrect. You can take DNP up to a certain level without too much acceleration of body temperature, heart rate, respiration rate, etc. Then, just a little more and everything goes out of control. Someone trying to see the side-effects expected from the 1930's usage used increasing amounts without too much effect. Then, it went out of control with pulse above 180, extremely fast respiration, consumption of 1 liter of fluid every 20 minutes and problems controlling body temperature even laying naked on a cold waterbed, heating closed, all windows open in minus 10-15C weather and fan blowing at maximum directly on body.
Initial protocol was to use around 500 mg every 2 days for an expected loss of 0.5 lbs of fat per dose in order to avoid accumulation from the around 36 hours half life. To protect against extreme oxydation, 4 grams of vitamin C were taken every 2to 4 hours. Experimenter found it more useful to take very small doses througout the day going by feeling. Experimenter was very tuned to what was going on in his body and that may explain the lack of issues in that specific case.
To answer the initial question:
The uncoupling of the phosphorylation of ADP to ATP by DNP alone could not have lead to reported fat loss. There is of course acceleration of the metabolic processes to evacuate the extra heat. The value of this is difficult to evaluate but is significant. Expect around 0.5 lbs of fat loss per 500 mg dosage. At a 'safer' dosage of 250mg a day you should get around 7lbs of pure fat loss within a month even if individual is already below 6%.
The maximum dosage that I have seen someone use (6'4" and over 300lbs but fit) is 1000 mg a day. In most individuals this will lead to a very long period of extreme heat removal and-or death.
As within any advanced bodybuilding approach (especially biochemical optimisation) someone should cover the basis first. That means healthy diet, comprehensive vitamins-minerals-supplements, highly trained VO2Max and a person without dieseases in general. I would expect someone who takes it 20 years later to use additional:
-CLA with Lecithin
-ALCAR
-co-Q-10
-lipoic acid
-any and all anti-oxydant
Be safe and use biochemistry for better living.