When Im at the range shooting groups I load every chamber. If Im hunting, on horse back or doing a lot of walking I carry as FA suggest.
The Mod 83 has a safety bar and a hammer safety position. When the hammer is in the safety position the safety bar is physically between the hammer and the receiver. This prevents the hammer from making contact with the firing pin. Pulling the trigger has no effect on the hammer when the hammer is in the safety position. Even though the Mod 83 is equipped with this safety feature FA suggest taking an extra measure of safety and carry with the hammer over an empty chamber.
Ultimately its up to you how you carry your gun. I personally dont see a need to carry all five when Im in the field. I have never felt to be at a disadvantage by only loading four cartridges.
Take Care,
Scott