What are the assumptions made during the calculation of net gain of $ATP$?

(N/A) For the theoretical calculation of $ATP$ molecules,various assumptions are made,which are as follows:
$(a)$ It is assumed that various parts of aerobic respiration such as glycolysis,$TCA$ cycle,and $ETS$ occur in a sequential and orderly pathway.
$(b)$ $NADH$ produced during the process of glycolysis enters into the mitochondria to undergo oxidative phosphorylation.
$(c)$ The glucose molecule is assumed to be the only substrate,and it is assumed that no other molecule enters the pathway at intermediate stages.
$(d)$ The intermediates produced during respiration are not utilized in any other metabolic process.