If you are certain the wine is fully fermented to dry and cleared.. go ahead and bottle it. You don't have to add these chemicals..I will say that you will have to consider carefully the length of time you intend to store your wine before drinking. If your wine is finished dry and you intend to consume early.. there really is no need to add them. I will say though, that if you do choose to add sorbate.. you must add sulphite before sorbate. Sorbate can never be added on its own and it must be added in a sulphite / sorbate order.
Sorbate is added before backsweetening and after all fermentation is finished.. because it stops yeast reproducing itself. So if you sweeten again via fpack or simple sugar syrup, the yeast won't kick back into high gear and continue turning sugar into alcohol. It's also a preservative.
Sulphite is also a preservative. If you want to cellar your wines for any length of time.. particularly over a year..You can't add sorbate on its own..if you do you will add a 'geranium' taste and smell to your finished wine.. this is why most textbooks will advise the addition of sulphite before sorbate to stabilise the finished wine.
There is no known remedy at this time,as far as I am aware, for the geranium fault in a wine.
Not all recipes or recipe books will go into the details of modern chemical additions in fruit or grape wines. Some are very old and conceived well before we had a more coldblooded scientific approach to winemaking..
Allie