Bioequivalence and Bioavailability Forum

Dear all!
I've noted that sample size, estimated with the help of PowerTOST's scABEL, depends on the difference between CV_T and CV_R.
Suppose we have a HVD with unknown CV (or CV is known in literature but it ranges widely through the studies). There could be a situation when CV_T and CV_R do not coincides. For example, CV_R=0.3 and CV_T=0.4. Then basing on the sampleN.scABEL for theta0=0.9 we need 48 subjects. But if we plan replicate study on the basis of CV=0.3 we get only 34 subjects. Moreover planing replicate study without scaling (sampleN.TOST) we get only 40 subjects. Here I post the graph for illustration purposes (scABEL2 denotes sampleN.scABEL(CV=c(CV_T, 0.3), theta0=0.9, design="2x2x4"))
Do I undestand correctly? If it so then there are always exist a miserable possibility that calculated by scABEL with CV_T=CV_R sample size would be insufficient?