Pressure is defined as force per unit area. That being the case pressures applied in the model must be calculated using proper units or converted to the proper units. It sounds like you're on the right track.
Remember that things really don't have units in Ansys. If the distance between two nodes is 1.00 this could be in inches, meters, etc. You just need to make sure temperatures, material properties, loadings, and so forth are consistent.
It's a good idea to use the /units command to declare units for the model. These units can later be referenced by you or another use using the /stat command.
-Brian