Classic Shirt pattern confusion

Step: Make the wearer's right set-in placket (View A) The instructions call for a 1" fabric strip to be cut; ok. The instructions call for a 1" interfacing strip. Fine. The instructions call for a 1/2" row of basting stitch. Here is the beginning of the trouble: that would place the basting stitch down the very center of the placket strip. But the instructions say to align the interfacing with the basting. That would have HALF of the interfacing hanging off one edge of the cut placket strip. Using the Key, and assuming it is correct that the fabric strip is only 1" wide, the picture shows interfacing only on the center 1/2" of the strip, leaving 1/4" free at the top and at the bottom (the bottom would then be folded up. Therefore, shouldn't the interfacing strip only be 1/2" wide with 1/4" fold? Or, is it wrong to say that the basting belongs in the center of the strip, since the picture shows it at the bottom 1/4? Somehow, the instructions and the pictures don't match. Please reply to eboepple1@gmail.com ASAP if possible. Thank you.