Subject Line Test from Email Send Program Sent Wrong Amount

I just executed an email send program with a subject line A/B test.  The test sample was sent first, as expected, and I sent the test population to 20% for 2 programs, one program of 5k+ and one of 4k+.  The system then sent the test send, but only roughly 70 and 80 emails were sent, and the programs are showing membership in the 70-80 range.  I double checked amount send and target group size, nothing stands out, but the send amount was far from 20%.  Any ideas what may be wrong, or what I may have done incorrectly?