vintage Schoeller light weight black snow pants Size 6 but fits like a size 4

Schoeller light weight black snow pants. In perfect vintage condition. It says Size 6 but feel more like a size 4 These gorgeous pants a foot wrap and a front zipper. No pockets at all ! It’s a stretchy material and super comfortable to wear . No bulky at all . Here are the measurements. Length is 34 to the bottom hem and 41 to the bit of the foot. Waist is 13 Inseam is 24 Crotch is 13 Hips are 19