it may depend on how the drivers are positioned inside the pads.
you have angled drivers and you have parallel / direct firing into the ear canal drivers.
if you if you adjust the up /down position, and the forward /back position of the axis of the driver, by moving the headband forward, and provided that you do not make a up/down adjustment on the headband, what you are then doing is a diagnol adjustment.
in the case of angled drivers you are changing the firing axis onto a different part of the ear canal.
so what you could conceiviblybe doing is changing the perceived brightness / detail and therefore the perceived soundstageing.
But first you should really try the up / down adjustments. On my Beyers I find that I have to make them really snug (up/down). I find little need for a forward / back adjust ment, as I do it almost automatically. unfortunately this tends to give me top of head burn with the DT880.
On my Grado SR80 / Aiwa AK100 modification I adjusted the driver to my ear for best comfort and best sound, tuned to my ear, before cementing everything in place. It therefore is most comfortable without any need for adjustment.