Someone else had a problem similar to this and I vaguely recall that the solution was that the setting had to be selected before running the study. You might search through the forums for it. The other one might have been about stress units but it might point you in the right direction.
As you know simulation results' number format can be changed in simulation>options>default options>color chart>number format. But I really doubt it if it is possible to be changed in SimXpress even in 2017 (left 1% of possibility, in case if I am missing something )
Hi Siavash / James
This is the my point.
I raised this issue a while ago and the problem was unless you had the Premium package you could not change the units, you were stuck with scientific results.
If you had the Premium package then you could right click on the results and change.
I raised an ER on this to get SolidWorks to let you change the units on any package Premium, Professional or Standard.
I was told this would be implemented and the ER was closed out, seems that it hasn't been implemented.