fix heat for thermal conductivity

Dear Lammps users:
I am using fix heat command to calculate thermal conductivity, and I have some questions about this command.
This is part of my in file:
fix hot all heat 10 2 region hot
fix cold all heat 10 -2 region cold
run 2000000
And I calculate thermal conductivity with equation, K = Ф/(Areatemperature gradient), the units of Фis W, and timestep is 0.0005ps. “2” means rate of heat addition or subtraction is 2eV/ps, and total time is 20000000.0005ps=1000ps, so the total energy that add to the group is 21000eV.And then Ф=(20001.60210^(-19)J) /(100010^(-12)s)=3.204*10^(-7)W.
Am I right?

Best regards!