How exactly do you "force users off at the end of each month"? (Please be aware that I'm UEMdev, and don't know much about Horizon :-)
If that nicely logs off users, UEM's export at logoff should take place as usual. If it's a bit more abrupt than that, then the command you quoted is the correct one.
I use the horizon api, which is "supposed to" do a nice logoff, but I'm not sure it is. I may try and run the command manually then. I've been doing some testing and some settings don't seem to save when I force the logoff, but if the user logs off they do.