Using the Fist of Steel as Heavy, if you are being over healed already before the fist were out, the overheal would still go to 450. and the opposite is true. if you were to have the fist out, swap weapons, you're now limited to 390 overheal.

Using the Fist of Steel as Heavy, if you were to swap to your secondary before swapping to your primary, even just for a frame, it removes the swap speed delay built into the fist of steel. (this might also apply to other related weapons that have the same delay)