Whether what your wearing applies movement penalties separate from penalties simply the weight of the item and whether the item your holding applies movement penalties separate from penalties simply the weight of the item are somewhat related, but one is not required for the other to exist. It seems odd to me to try to combine the mechanics for penalties based on what item is equipped and what clothing your wearing and for items you have in your hand, and still have them derived from the weight of the item.
The way I see it, the total weight being weight carried should cause movement penalties, the unwieldiness of the item that is equipped could affect your control of weapons, ability to melee, climbing ability, and such, but doesn’t need to impact your ability to run, and finally, clothing could simply affect stats without some weird equation based on two number values that would be constant to that article of clothing (weight and weight multiplier when equipped)