Answer:

Yes, the user can add factors on the vessel foundation load separately for the liquid content inside the vessel as well as factor on the vessel weight itself. Go to Vessel Properties>Load Conditions, and then enter the factors under Factor on Liquid and Factor on Weight as shown below (in the example 1.5 is used):

The total foundation load before applying factor as seen in the report for a horizontal vessel was 9588 daN.

After applying 1.5 factor the foundation load is 9588 x 1.5 = 14381 daN.