The soft limits trigger if the value inputted is either less than the rec_min tag or above the rec_max tag. Soft limits are established for values that are unlikely to be associated with the parameter. These values might not break the science model, but may create strange results. The default color for cells taht exceed the soft limits is yellow.
If any values in the set of files for the current management file exceed the soft limits, you will get a warning as you save stating that the results may be strange after a WEPS run.