SM - PLot - transverse energy of neutrinos vs cross section

Hi,

I wanna obtain a background for the process p p -> nu, Nu, A (nu is any neutrino, Nu is any antineutrino). I mean that I wanna obtain the plot: missing transverse energy of neutrinos vs cross section (or number of events ). First I tried the way;

1- choose SM
2- Enter the process
3- square diagrams
4- make&launch
5- choose pdf sets and first, second particle momentums
6- Goes to Monte Carlo Simulation
7- Set Distributions as Z(ne,Ne) min. 100, max. 1000, Z(nm,Nm) min. 100 max.1000, Z(nt,Nt) min. 100 max. 1000
8- Start integration
9- Display Distribution -> choose which one you wanna see.

via this procedure,I obtain distributions of each subprocess coming from the main process above. Then, I add up all of them and obtain one plot.

Is this way correct? When I do these calculations in three different pc with following same procedure (for checking the results), ı obtain three different distributions. Therefore, ı think that I did something wrong. Why we could not obtain the same plot?