Making an a-line skirt for the Burda dress

I want to make a flared, basically an A-line skirt for this dress.
First I made a muslin with the original pattern which is a pencil skirt. I took the same size as for the dress, which 1 size smaller than my measurements.
I only sew up the upper part of the skirt because I was interested in the fit around the waist and hip area. The fit is good. It has slightly more ease than a skirt would have but that's because it is made for a dress. It doesn't have to sit tightly around the waist...
To draft an A-line skirt I used my Mom's diagram here (she did a pattern drafting course somewhere back in the eighties and she gave me her notes)



- One thing I corrected first is that I've straightened out all of the lines from the hips below. As I mentioned the original skirt is a pencil skirt which is narrower at the bottom. - Then I opened up the dart and cut the pattern open straight from the dart point down.
By pivoting I closed the top points of the dart, this opened up the lower part. This way I basically transferred the extra ease to the lower part of the skirt:



- I added extra 4 cm (1.6'') to the side seam at the bottom and from there I drew a line up to the widest part if the hips:



- Filled the empty spaces up by attaching another piece of paper. This is it! The measurements of the new pattern are exactly the same as the original one.
A good tutorial, which basically explains the same is to find here.
(Note: The tutorial in the link instructs to take 1/2 of the width of the inserted piece after closing the darts. For me it is the same as the 4 cm my mom's book istructed)



Just to be sure, I made a muslin of the new skirt pattern. As usually I only made the top part to get to see the fit around the waist and hips. I also basted a zipper in the dress muslin to get a better view.  (The wrinkles are caused by the zipper which I only basted but not securely inserted.)
The only thing I need to change is to slightly lengthen the bodice back in the middle. When sewing I already added about 6 mm all around in the length. On the pics below looks like it is perfectly straight but in reality I need to add about 1 cm. I guess it is  a minimal swayback adjustment. The skirt looks perfect, the side seam lies perfectly in the middle: