Finished waist too small

I thought I'd start a new post for my problem, so it didn't get confused with the opposite problem previously reported in another thread. I believe @Ejensewchat has had the same problem (unsure of which size she was sewing) I've made the size 14 Girl Friday culottes and the finished waist has turned out about 3 inches smaller than intended. I have rechecked my drafted pattern pieces against the original pattern and all three relevant pieces (front, back and waistband) are exactly size 14 with all notches and markings transferred exactly as per the pattern. I've re-read the instructions for creating the back darts, front and back box pleats and the front pleats. I believe I have sewn all of these correctly. When I went to attach the waistband it was considerably LONGER than the culottes. I foolishly thought the culottes were fitting OK so I trimmed the waistband to fit the culottes and it has all ended up far too small (finished waist of about 31" instead of 34.5") After checking that the pattern pieces were drafted correctly I pinned all the pleats in the drafted interfacing pieces, overlapped the side seams such that the notches were aligned (as they get basted when constructing the pockets). Still the waistband is about 2-3 inches longer than the pants would be. Thus, my pattern pieces (which match the original pattern) are giving me the same problem as my cut fabric did. When the center waistband notch is aligned with the pinned side seam, all of the other waistband notches are 0.5" or more beyond the corresponding notch on the pants. It would appear that the waistband is the right length. I can not see how I am going wrong such that my pants are ending up so much smaller than my waistband. Help please @Liesl....