For some of Misa's skills it mentions it ignores additional def according to levels of winding spring so please check if the tooltip is correct. Tested it and it doesn't seem to ignore additional def as mentioned at all from both buffs. Either fix or change tooltip because its misleading.
You can be confused because when you use winding-up (winding spring and we changed it in eu version) buff skill , the winding-up buff skill level downed and downed whenever you use Popularna, Machina buster or EMP-0314 and you need to re-buff winding-up buff skill periodically for max DMG.
Please check again. I tested on 320 Def mobs with max electric charging at 0 winding spring with attack filler to compensate the loss of 1 AR. And with max electric charging + max winding spring without attack filler. Amounts to the same damage for Popularna. If the IDEF is working the damage with max winding spring should be higher than that without. Attached are the captioned screenshots.