Staad Pro Area, One Way and Floor Loads - Uniformly Varying

in the Staad Pro manual it says the following about Area, One Way and Floor loads:

G.15.3 Area, One-way, and Floor Loads

The following assumptions are made while transferring the area/floor load to member load:

  1. The member load is assumed to be a linearly varying load for which the start and the end values may be of different magnitude.

I'm trying to understand if it is possible to use define a varying load. Other locations in the manual state that the pressure must be uniform. Is it possible to make the load varying?