Try adding these lines (listed on the compute stress/atom doc page)
to any of the bench/in.* scripts:
compute peratom all stress/atom
compute p all reduce sum c_peratom[1] c_peratom[2] c_peratom[3]
variable press equal -(c_p[1]+c_p[2]+c_p[3])/(3*vol)
thermo_style custom step temp etotal press v_press
Except for in.rhodo (which has a PPPM contribution which is not
included in stress/atom), you will see the output of the global
pressure and summed per-atom stresss is the same.
Steve