In reply to Andi.

17% is approximately 20%, and that is what this simulation should show because you are simulating the power of the test (P(reject H0| H1 is true)) when N=70. Look at the first few observations of the EQUIV data set and you will see that PROC TTEST is asking whether a certain confidence interval about the sample mean is entirely within the interval [-0.05, 0.05]. The value of alpha determines the width of the CI.