What advantages are gained by separating fixed expenses from variable expenses? It has been said that the statement “fluctuating overheads are those which vary with output” is an unjustifiable...

What advantages are gained by separating fixed expenses from variable expenses? It has been said that the statement “fluctuating overheads are those which vary with output” is an unjustifiable simplification. How would you qualify the statement? How would your qualification affect your treatment of fluctuating overheads when compiling costs?