Case 6 provides the stresses for the Code's requirement (the sum of the occasional stresses and the sustained stresses). The stresses are the only useful information from this load case. You would not need to evaluate loads or displacements from this load case.

As you indicated above, a 7th case can be constructed for load/maintenance evaluation. This case however is NOT a stress compliance case (it may yield different stress results from case 6 based on the non-linear boundary conditions of the system). Therefore, since this is not a stress compliance case, you could specify that the load case stress type is OPE. Assuming you're running B31.1 or B31.3, this will produce a stress report (which you shouldn't really look at) with ZERO allowable values. This way, no one can mis-interpret the stress results.