As there have been no replies to this I'll throw in my two penn'th of non expert advice.
Drafting an A-line skirt isn't quite as simple as you make it sound.
The waist generally needs to be snug but not so tight that you can't breath. With a stretchy fabric like ponte an inch or so of negative ease would be OK, but you don't want negative ease in the hip area. That means that you need darts - or a very wide A-line shape to get the necessary increase in width.
When you made A-line skirts by slashing and spreading you will have introduced a curve into the hemline. If you cut straight across you will end up with a skirt which is longer at the sides than at front and back. Apart from fitting alterations, which only add or subtract a small amount, the length of a skirt from waist to hem should be the same all round (unless it's a deliberate high-low hemline). The wider the A the more curved the hem will become.