No, you don't have to re-perform every exercise. Once you enter in your numbers and have the 1RMs figured out, you're done. Every workout card you print out will have the appropriate weight figured out and listed for you.
Now...after I said that...if you find that the weight listed on the workout card is either too light or too heavy, you can change it. For example, the weight listed for my deadlifts was for 25 lb dumbbells. I can't quite do 25s safely though, so I changed my number to 22 lb dumbbells on my workout card, and my 1RM for this exercise was refigured for the rest of the STS workouts.