301-11.200—Under what circumstances may my agency prescribe a reduced per diem rate lower than the prescribed maximum?
         Under the following circumstances:
    
    
        
        (a) 
         When your agency can determine in advance that lodging and/or meal costs will be lower than the per diem rate; and
    
    
        
        (b) 
         The lowest authorized per diem rate must be stated in your travel authorization in advance of your travel.