I propose that movespeed that doesnt improves your %ms but a static amount such as Boots, Euls are calculated into the WHITE ms and only the % increase in GREEN. Boots and euls speed influences your % increase. Thus it would follow the same logic you did for Damage increased by attributes(which increases the white number) and %-auras or pure damage from weapons (which shows a green number) to seperate it.
Besides you would always see "350" ms when you die instead of "295" e.g.