During ETS, there is water formation as well from NADH2 and FADH2. From each NADH2 and each FADH2, 1 water moiety is obtained. Then if we look at the oxidation of 1 glucose molecule during respiration, there is formation of 10 NADH2 and 2 FADH2. So by above information, when this 10 NADH2 and 2 FADH2 will undergo ETS there should be formation of 12 water moiety, but in contrast we see only 6 water moiety in the equation of respiration. Why?