#1Page 1 Step 1 / Page 2 Step 5
Page 1 cutting, step 1, line 5 should read: 15 strips 1.5" x WOF; cut 5 of the strips in half making (10) 21" strips, sew each half strip to one full strip making 10 strips, and trim to 1.5" x 63.5" (also applies at page 2, step 5).
Official — designer correction see the source ↗