You are correct. There is a little difference between the chlorine/cya chart and the Pool Calc. They both work but the chart is a little more aggresive. It's safe to swim up to the shock level listed in the chart.

Thanks. Now if I could just test that high. My new test kit won't be here for a while and my local pool stores can't measure above 5ppm for FC either. So I really don't know how high mine is.

If your kit tests to 5 you can take 1 part pool water and 3 parts chlorine free water (measure carefully) and test it and multiply the result by 4. It is very inprecise but it'll give you a ballpark number.