  Recently a number of authors have used a system of branes and antibranes at
finite temperature for microscopic modeling of non-extremal black holes in
string theory. The entropy of the system is derived from the simplified
assumption of decoupled gas of open strings on the stacks of branes and
antibranes and extremizing the total entropy with respect to the number of
branes (or antibranes). The resulting entropy differs from the supergravity
entropy by a deficit factor. We give an intuitive explanation for the deficit
factor. We treat the whole system as two stacks of branes and antibranes with a
single copy of Yang-Mills gas common to both the stacks. This gives the answer
in agreement with the supergravity.
